**Update**

We discussed and decide this CLI should always only clean up pods created by Airflow.

<hr>

### Description

Currently command `kubernetes cleanup-pods` cleans up Pods that meet specific conditions in a given namespace.

Underlying code: https://github.com/apache/airflow/blob/2.0.1/airflow/cli/commands/kubernetes_command.py#L70

### Use case / motivation

The problem to me is: users may have other non-Airflow stuff running in this specific namespace, and they may want to have different strategy/logic for Pod cleaning-up for these non-Airflow pods.

We may want to have an additional boolean flag for this command, like `--only-airflow-pods`, so that users can decide if they only want to clean up Airflow-created Pods.

It should not be hard to identify Airflow-created pods, given the specific labels Airflow adds to the Pods it creates (https://github.com/apache/airflow/blob/2.0.1/airflow/kubernetes/pod_generator.py#L385)




airflow/cli/cli_parser.py
func = import_string(import_path)
        return func(*args, **kwargs)
    command.__name__ = name
    return command
class DefaultHelpParser(argparse.ArgumentParser):
    """CustomParser to display help message"""
    def _check_value(self, action, value):
        """Override _check_value and check conditionally added command"""
        executor = conf.get('core', 'EXECUTOR')
        if value == 'celery' and executor not in (CELERY_EXECUTOR, CELERY_KUBERNETES_EXECUTOR):
            message = f'celery subcommand works only with CeleryExecutor, your current executor: {executor}'
            raise ArgumentError(action, message)
        if value == 'kubernetes':
            try:
                import kubernetes.client  
            except ImportError:
                message = (
                    'The kubernetes subcommand requires that you pip install the kubernetes python client.'
                    "To do it, run: pip install 'apache-airflow[cncf.kubernetes]'"
                )
                raise ArgumentError(action, message)
        if action.choices is not None and value not in action.choices:
            check_legacy_command(action, value)
        super()._check_value(action, value)
    def error(self, message):
        """Override error and use print_instead of print_usage"""
        self.print_help()
        self.exit(2, f'\n{self.prog} command error: {message}, see help above.\n')
_UNSET = object()
class Arg: