**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
with mock.patch('airflow.executors.kubernetes_executor.watch') as mock_watch:
            mock_watch.Watch.return_value.stream.return_value = self.events
            latest_resource_version = self.watcher._run(
                self.kube_client,
                self.watcher.resource_version,
                self.watcher.scheduler_job_id,
                self.watcher.kube_config,
            )
            assert self.pod.metadata.resource_version == latest_resource_version
    def assert_watcher_queue_called_once_with_state(self, state):
        self.watcher.watcher_queue.put.assert_called_once_with(
            (
                self.pod.metadata.name,
                self.watcher.namespace,
                state,
                self.core_annotations,
                self.pod.metadata.resource_version,
            )
        )
    def test_process_status_pending(self):