**Apache Airflow version**:  1.10.10


**Kubernetes version (if you are using kubernetes)** (use `kubectl version`): v1.15.11

KubernetesPodOperator truncates logs when container produces more than 10 lines of logs before execution of `read_pod_logs` function. Is there any reason to make 10 as default value for `tail_lines` argument ?
```python
    def read_pod_logs(self, pod: V1Pod, tail_lines: int = 10):
        """Reads log from the POD"""
        try:
            return self._client.read_namespaced_pod_log(
                name=pod.metadata.name,
                namespace=pod.metadata.namespace,
                container='base',
                follow=True,
                tail_lines=tail_lines,
                _preload_content=False
            )
        except BaseHTTPError as e:
            raise AirflowException(
                'There was an error reading the kubernetes API: {}'.format(e)
            )
```
kubernetes_tests/test_kubernetes_pod_operator.py
fixture = sys.path[0] + '/tests/kubernetes/basic_pod.yaml'
        k = KubernetesPodOperator(
            task_id="task" + self.get_current_task_name(),
            in_cluster=False,
            pod_template_file=fixture,
            do_xcom_push=True
        )
        context = create_context(k)
        result = k.execute(context)
        self.assertIsNotNone(result)
        self.assertDictEqual(result, {"hello": "world"})
    def test_pod_template_file_with_overrides_system(self):
        fixture = sys.path[0] + '/tests/kubernetes/basic_pod.yaml'
        k = KubernetesPodOperator(
            task_id="task" + self.get_current_task_name(),
            labels={"foo": "bar", "fizz": "buzz"},
            env_vars=[k8s.V1EnvVar(name="env_name", value="value")],
            in_cluster=False,
            pod_template_file=fixture,
            do_xcom_push=True
        )
        context = create_context(k)
        result = k.execute(context)
        self.assertIsNotNone(result)
        self.assertEqual(k.pod.metadata.labels, {'fizz': 'buzz', 'foo': 'bar'})
        self.assertEqual(k.pod.spec.containers[0].env, [k8s.V1EnvVar(name="env_name", value="value")])
        self.assertDictEqual(result, {"hello": "world"})
    def test_init_container(self):