**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
scheduler_name = "default-scheduler"
        k = KubernetesPodOperator(
            namespace="default",
            image="ubuntu:16.04",
            cmds=["bash", "-cx"],
            arguments=["echo 10"],
            labels={"foo": "bar"},
            name="test-" + str(random.randint(0, 1000000)),
            task_id="task" + self.get_current_task_name(),
            in_cluster=False,
            do_xcom_push=False,
            schedulername=scheduler_name
        )
        context = create_context(k)
        k.execute(context)
        actual_pod = self.api_client.sanitize_for_serialization(k.pod)
        self.expected_pod['spec']['schedulerName'] = scheduler_name
        self.assertEqual(self.expected_pod, actual_pod)
    def test_pod_node_selectors(self):