**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)
            )
```
airflow/kubernetes/pod_launcher.py
"""Read POD information"""
        try:
            return self._client.read_namespaced_pod(pod.metadata.name, pod.metadata.namespace)
        except BaseHTTPError as e:
            raise AirflowException(
                'There was an error reading the kubernetes API: {}'.format(e)
            )
    def _extract_xcom(self, pod: V1Pod):
        resp = kubernetes_stream(self._client.connect_get_namespaced_pod_exec,
                                 pod.metadata.name, pod.metadata.namespace,
                                 container=PodDefaults.SIDECAR_CONTAINER_NAME,
                                 command=['/bin/sh'], stdin=True, stdout=True,
                                 stderr=True, tty=False,
                                 _preload_content=False)
        try:
            result = self._exec_pod_command(
                resp, 'cat {}/return.json'.format(PodDefaults.XCOM_MOUNT_PATH))
            self._exec_pod_command(resp, 'kill -s SIGINT 1')
        finally:
            resp.close()
        if result is None:
            raise AirflowException('Failed to extract xcom from pod: {}'.format(pod.metadata.name))
        return result
    def _exec_pod_command(self, resp, command):