**Apache Airflow version**: 2.0.1


**Kubernetes version (if you are using kubernetes)** (use `kubectl version`): 1.20.5

**Environment**:

- **Cloud provider or hardware configuration**: Azure AKS

**What happened**:

When task or dag name is defined with a non ascii character, pod creations fails with a kubernetes.client.rest.ApiException: (422)
(task maintains scheduled status)
this is because the hostname defined for the pod is based on dag and task name...

**What you expected to happen**:

Create the pod and run the task

**How to reproduce it**:
Run a task with name "campaña" on K8s executor,

Error log
```
{"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"Pod \"dagnamecampaña.0fb696e661e347968216df454b41b56f\" is invalid: metadata.name: Invalid value: \"dagnamecampaña.0fb696e661e347968216df454b41b56f\": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0
-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')","reason":"Invalid"
```



tests/executors/test_kubernetes_executor.py
self, mock_delete_pod, mock_get_kube_client, mock_kubernetes_job_watcher
    ):
        executor = self.kubernetes_executor
        executor.kube_config.delete_worker_pods_on_failure = True
        executor.start()
        key = ('dag_id', 'task_id', 'ex_time', 'try_number2')
        executor._change_state(key, State.FAILED, 'pod_id', 'test-namespace')
        assert executor.event_buffer[key][0] == State.FAILED
        mock_delete_pod.assert_called_once_with('pod_id', 'test-namespace')
    @mock.patch('airflow.executors.kubernetes_executor.KubernetesExecutor.adopt_launched_task')
    @mock.patch('airflow.executors.kubernetes_executor.KubernetesExecutor._adopt_completed_pods')
    def test_try_adopt_task_instances(self, mock_adopt_completed_pods, mock_adopt_launched_task):
        executor = self.kubernetes_executor
        executor.scheduler_job_id = "10"
        ti_key = annotations_to_key(
            {
                'dag_id': 'dag',
                'execution_date': datetime.utcnow().isoformat(),
                'task_id': 'task',
                'try_number': '1',
            }
        )