**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
"""We try to find pods only once per scheduler id"""
        executor = self.kubernetes_executor
        mock_kube_client = mock.MagicMock()
        executor.kube_client = mock_kube_client
        mock_tis = [
            mock.MagicMock(queued_by_job_id="10", external_executor_id="1", dag_id="dag", task_id="task"),
            mock.MagicMock(queued_by_job_id="40", external_executor_id="1", dag_id="dag", task_id="task2"),
            mock.MagicMock(queued_by_job_id="40", external_executor_id="1", dag_id="dag", task_id="task3"),
        ]
        executor.try_adopt_task_instances(mock_tis)
        assert mock_kube_client.list_namespaced_pod.call_count == 2
        mock_kube_client.list_namespaced_pod.assert_has_calls(
            [
                mock.call(namespace='default', label_selector='airflow-worker=10'),
                mock.call(namespace='default', label_selector='airflow-worker=40'),
            ],
            any_order=True,
        )
    @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_no_matching_pods(