**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
monitor_mock):  
        from airflow.utils.state import State
        client = kube_client.get_kube_client(in_cluster=False)
        name = "test"
        namespace = "default"
        k = KubernetesPodOperator(
            namespace='default',
            image="ubuntu:16.04",
            cmds=["bash", "-cx"],
            arguments=["sleep 1000"],
            labels={"foo": "bar"},
            name="test",
            task_id=name,
            in_cluster=False,
            do_xcom_push=False,
            termination_grace_period=0,
        )
        context = create_context(k)
        monitor_mock.return_value = (State.SUCCESS, None)
        k.execute(context)
        name = k.pod.metadata.name
        pod = client.read_namespaced_pod(name=name, namespace=namespace)
        self.assertEqual(pod.status.phase, "Running")
        k.on_kill()
        with self.assertRaises(ApiException):
            pod = client.read_namespaced_pod(name=name, namespace=namespace)