**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
self.log.info(
            'Event: %s had an event of type %s',
            event.metadata.name, event.status.phase)
        status = self.process_status(event.metadata.name, event.status.phase)
        return status
    def pod_not_started(self, pod: V1Pod):
        """Tests if pod has not started"""
        state = self._task_status(self.read_pod(pod))
        return state == State.QUEUED
    def pod_is_running(self, pod: V1Pod):
        """Tests if pod is running"""
        state = self._task_status(self.read_pod(pod))
        return state not in (State.SUCCESS, State.FAILED)
    def base_container_is_running(self, pod: V1Pod):
        """Tests if base container is running"""
        event = self.read_pod(pod)
        status = next(iter(filter(lambda s: s.name == 'base',
                                  event.status.container_statuses)), None)
        if not status:
            return False
        return status.state.running is not None
    @tenacity.retry(
        stop=tenacity.stop_after_attempt(3),
        wait=tenacity.wait_exponential(),
        reraise=True
    )
    def read_pod_logs(self, pod: V1Pod, tail_lines: int = 10):