**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
mock_api_client.sanitize_for_serialization.return_value = {}
        mock_kube_client.api_client = mock_api_client
        config = {
            ('kubernetes', 'pod_template_file'): path,
        }
        with conf_vars(config):
            kubernetes_executor = self.kubernetes_executor
            kubernetes_executor.start()
            
            try_number = 1
            kubernetes_executor.execute_async(
                key=('dag', 'task', datetime.utcnow(), try_number),
                queue=None,
                command=['airflow', 'tasks', 'run', 'true', 'some_parameter'],
            )
            kubernetes_executor.sync()
            kubernetes_executor.sync()
            assert mock_kube_client.create_namespaced_pod.called
            assert not kubernetes_executor.task_queue.empty()
            
            mock_kube_client.create_namespaced_pod.side_effect = None
            
            kubernetes_executor.sync()
            assert mock_kube_client.create_namespaced_pod.called
            assert kubernetes_executor.task_queue.empty()
    @mock.patch('airflow.executors.kubernetes_executor.KubeConfig')
    @mock.patch('airflow.executors.kubernetes_executor.KubernetesExecutor.sync')
    @mock.patch('airflow.executors.base_executor.BaseExecutor.trigger_tasks')
    @mock.patch('airflow.executors.base_executor.Stats.gauge')
    def test_gauge_executor_metrics(self, mock_stats_gauge, mock_trigger_tasks, mock_sync, mock_kube_config):