**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 should not adopt any tasks that were not assigned by the scheduler.
        This ensures that there is no contention over pod management.
        """
        executor = self.kubernetes_executor
        executor.scheduler_job_id = "modified"
        pod_ids = {"foobar": {}}
        pod = k8s.V1Pod(
            metadata=k8s.V1ObjectMeta(
                name="foo",
                labels={"airflow-worker": "bar"},
                annotations={
                    'dag_id': 'dag',
                    'execution_date': datetime.utcnow().isoformat(),
                    'task_id': 'task',
                    'try_number': '1',
                },
            )
        )
        executor.adopt_launched_task(mock_kube_client, pod=pod, pod_ids=pod_ids)
        assert not mock_kube_client.patch_namespaced_pod.called
        assert pod_ids == {"foobar": {}}
    @mock.patch('airflow.executors.kubernetes_executor.KubernetesJobWatcher')
    @mock.patch('airflow.executors.kubernetes_executor.get_kube_client')
    @mock.patch('airflow.executors.kubernetes_executor.AirflowKubernetesScheduler')
    def test_pending_pod_timeout(self, mock_kubescheduler, mock_get_kube_client, mock_kubernetes_job_watcher):