**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
#
#
import unittest
import mock
from requests.exceptions import BaseHTTPError
from airflow.exceptions import AirflowException
from airflow.kubernetes.pod_launcher import PodLauncher
class TestPodLauncher(unittest.TestCase):
    def setUp(self):
        self.mock_kube_client = mock.Mock()
        self.pod_launcher = PodLauncher(kube_client=self.mock_kube_client)
    def test_read_pod_logs_successfully_returns_logs(self):
        mock.sentinel.metadata = mock.MagicMock()
        self.mock_kube_client.read_namespaced_pod_log.return_value = mock.sentinel.logs
        logs = self.pod_launcher.read_pod_logs(mock.sentinel)
        self.assertEqual(mock.sentinel.logs, logs)
    def test_read_pod_logs_retries_successfully(self):