Kubernetes tests are failing master build:

Example here:

https://github.com/apache/airflow/actions/runs/350798991


The failing test is:

```
_______________ TestKubernetesPodOperatorSystem.test_pod_failure _______________

self = <kubernetes_tests.test_kubernetes_pod_operator.TestKubernetesPodOperatorSystem testMethod=test_pod_failure>

    def test_pod_failure(self):
        """
        Tests that the task fails when a pod reports a failure
        """
        bad_internal_command = ["foobar 10 "]
        k = KubernetesPodOperator(
            namespace='default',
            image="ubuntu:16.04",
            cmds=["bash", "-cx"],
            arguments=bad_internal_command,
            labels={"foo": "bar"},
            name="test-" + str(random.randint(0, 1000000)),
            task_id="task" + self.get_current_task_name(),
            in_cluster=False,
            do_xcom_push=False,
        )
        with self.assertRaises(AirflowException):
            context = create_context(k)
>           k.execute(context)

kubernetes_tests/test_kubernetes_pod_operator.py:536: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
airflow/providers/cncf/kubernetes/operators/kubernetes_pod.py:313: in execute
    status = self.client.read_namespaced_pod(self.name, self.namespace)
.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/api/core_v1_api.py:19078: in read_namespaced_pod
    (data) = self.read_namespaced_pod_with_http_info(name, namespace, **kwargs)  # noqa: E501
.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/api/core_v1_api.py:19169: in read_namespaced_pod_with_http_info
    collection_formats=collection_formats)
.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/api_client.py:345: in call_api
    _preload_content, _request_timeout)
.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/api_client.py:176: in __call_api
    _request_timeout=_request_timeout)
.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/api_client.py:366: in request
    headers=headers)
.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/rest.py:241: in GET
    query_params=query_params)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

    def request(self, method, url, query_params=None, headers=None,
                body=None, post_params=None, _preload_content=True,
                _request_timeout=None):
        """Perform requests.
    
        :param method: http request method
        :param url: http request url
        :param query_params: query parameters in the url
        :param headers: http request headers
        :param body: request json body, for `application/json`
        :param post_params: request post parameters,
                            `application/x-www-form-urlencoded`
                            and `multipart/form-data`
        :param _preload_content: if False, the urllib3.HTTPResponse object will
                                 be returned without reading/decoding response
                                 data. Default is True.
        :param _request_timeout: timeout setting for this request. If one
                                 number provided, it will be total request
                                 timeout. It can also be a pair (tuple) of
                                 (connection, read) timeouts.
        """
        method = method.upper()
        assert method in ['GET', 'HEAD', 'DELETE', 'POST', 'PUT',
                          'PATCH', 'OPTIONS']
    
        if post_params and body:
            raise ValueError(
                "body parameter cannot be used with post_params parameter."
            )
    
        post_params = post_params or {}
        headers = headers or {}
    
        timeout = None
        if _request_timeout:
            if isinstance(_request_timeout, (int, ) if six.PY3 else (int, long)):  # noqa: E501,F821
                timeout = urllib3.Timeout(total=_request_timeout)
            elif (isinstance(_request_timeout, tuple) and
                  len(_request_timeout) == 2):
                timeout = urllib3.Timeout(
                    connect=_request_timeout[0], read=_request_timeout[1])
    
        if 'Content-Type' not in headers:
            headers['Content-Type'] = 'application/json'
    
        try:
            # For `POST`, `PUT`, `PATCH`, `OPTIONS`, `DELETE`
            if method in ['POST', 'PUT', 'PATCH', 'OPTIONS', 'DELETE']:
                if query_params:
                    url += '?' + urlencode(query_params)
                if re.search('json', headers['Content-Type'], re.IGNORECASE):
                    if headers['Content-Type'] == 'application/json-patch+json':
                        if not isinstance(body, list):
                            headers['Content-Type'] = \
                                'application/strategic-merge-patch+json'
                    request_body = None
                    if body is not None:
                        request_body = json.dumps(body)
                    r = self.pool_manager.request(
                        method, url,
                        body=request_body,
                        preload_content=_preload_content,
                        timeout=timeout,
                        headers=headers)
                elif headers['Content-Type'] == 'application/x-www-form-urlencoded':  # noqa: E501
                    r = self.pool_manager.request(
                        method, url,
                        fields=post_params,
                        encode_multipart=False,
                        preload_content=_preload_content,
                        timeout=timeout,
                        headers=headers)
                elif headers['Content-Type'] == 'multipart/form-data':
                    # must del headers['Content-Type'], or the correct
                    # Content-Type which generated by urllib3 will be
                    # overwritten.
                    del headers['Content-Type']
                    r = self.pool_manager.request(
                        method, url,
                        fields=post_params,
                        encode_multipart=True,
                        preload_content=_preload_content,
                        timeout=timeout,
                        headers=headers)
                # Pass a `string` parameter directly in the body to support
                # other content types than Json when `body` argument is
                # provided in serialized form
                elif isinstance(body, str):
                    request_body = body
                    r = self.pool_manager.request(
                        method, url,
                        body=request_body,
                        preload_content=_preload_content,
                        timeout=timeout,
                        headers=headers)
                else:
                    # Cannot generate the request from given parameters
                    msg = """Cannot prepare a request message for provided
                             arguments. Please check that your arguments match
                             declared content type."""
                    raise ApiException(status=0, reason=msg)
            # For `GET`, `HEAD`
            else:
                r = self.pool_manager.request(method, url,
                                              fields=query_params,
                                              preload_content=_preload_content,
                                              timeout=timeout,
                                              headers=headers)
        except urllib3.exceptions.SSLError as e:
            msg = "{0}\n{1}".format(type(e).__name__, str(e))
            raise ApiException(status=0, reason=msg)
    
        if _preload_content:
            r = RESTResponse(r)
    
            # In the python 3, the response.data is bytes.
            # we need to decode it to string.
            if six.PY3:
                r.data = r.data.decode('utf8')
    
            # log response body
            logger.debug("response body: %s", r.data)
    
        if not 200 <= r.status <= 299:
>           raise ApiException(http_resp=r)
E           kubernetes.client.rest.ApiException: (404)
E           Reason: Not Found
E           HTTP response headers: HTTPHeaderDict({'Content-Type': 'application/json', 'Date': 'Sat, 07 Nov 2020 07:33:13 GMT', 'Content-Length': '190'})
E           HTTP response body: {"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"pods \"test-815505\" not found","reason":"NotFound","details":{"name":"test-815505","kind":"pods"},"code":404}

.build/.kubernetes_venv/lib/python3.6/site-packages/kubernetes/client/rest.py:231: ApiException

```
airflow/providers/cncf/kubernetes/operators/kubernetes_pod.py
"""
    Execute a task in a Kubernetes Pod
    .. seealso::
        For more information on how to use this operator, take a look at the guide:
        :ref:`howto/operator:KubernetesPodOperator`
    .. note::
        If you use `Google Kubernetes Engine <https://cloud.google.com/kubernetes-engine/>`__
        and Airflow is not running in the same cluster, consider using
        :class:`~airflow.providers.google.cloud.operators.kubernetes_engine.GKEStartPodOperator`, which
        simplifies the authorization process.
    :param namespace: the namespace to run within kubernetes.
    :type namespace: str
    :param image: Docker image you wish to launch. Defaults to hub.docker.com,
        but fully qualified URLS will point to custom repositories. (templated)
    :type image: str
    :param name: name of the pod in which the task will run, will be used (plus a random
        suffix) to generate a pod id (DNS-1123 subdomain, containing only [a-z0-9.-]).
    :type name: str
    :param cmds: entrypoint of the container. (templated)
        The docker images's entrypoint is used if this is not provided.
    :type cmds: list[str]
    :param arguments: arguments of the entrypoint. (templated)
        The docker image's CMD is used if this is not provided.
    :type arguments: list[str]
    :param ports: ports for launched pod.
    :type ports: list[k8s.V1ContainerPort]