**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)
            )
```
tests/kubernetes/test_pod_launcher.py
mock.sentinel.metadata = mock.MagicMock()
        self.mock_kube_client.list_namespaced_event.side_effect = [
            BaseHTTPError('Boom'),
            mock.sentinel.events
        ]
        events = self.pod_launcher.read_pod_events(mock.sentinel)
        self.assertEqual(mock.sentinel.events, events)
        self.mock_kube_client.list_namespaced_event.assert_has_calls([
            mock.call(
                namespace=mock.sentinel.metadata.namespace,
                field_selector="involvedObject.name={}".format(mock.sentinel.metadata.name)
            ),
            mock.call(
                namespace=mock.sentinel.metadata.namespace,
                field_selector="involvedObject.name={}".format(mock.sentinel.metadata.name)
            )
        ])
    def test_read_pod_events_retries_fails(self):
        mock.sentinel.metadata = mock.MagicMock()
        self.mock_kube_client.list_namespaced_event.side_effect = [
            BaseHTTPError('Boom'),
            BaseHTTPError('Boom'),
            BaseHTTPError('Boom')
        ]
        self.assertRaises(
            AirflowException,
            self.pod_launcher.read_pod_events,
            mock.sentinel
        )
    def test_read_pod_returns_logs(self):