pause action uses --delete-local-data which is deprecated

[Drew Freiberger]

When performing a kubernetes node drain via the pause action, pods with emptydirs halt the drain process.

Please add an option to pass the --delete-emptydir-data flag to kubectl drain.

[George Kraft (cynerva)]

You can run the pause action with delete-local-data=true and it should cover your use case:

juju run-action kubernetes-worker/0 pause delete-local-data=true

This will call `kubectl drain` with --delete-local-data, which is equivalent to --delete-emptydir-data. They changed the name of the flag in Kubernetes 1.20, but the old flag still works. The action completes, but shows a warning:

unit-kubernetes-worker-0:
  UnitId: kubernetes-worker/0
  id: "2"
  results:
    Stderr: |
      Flag --delete-local-data has been deprecated, This option is deprecated and will be deleted. Use --delete-emptydir-data.
      WARNING: ignoring DaemonSet-managed Pods: ingress-nginx-kubernetes-worker/nginx-ingress-controller-kubernetes-worker-f5kz5
  status: completed
  timing:
    completed: 2021-01-08 19:10:32 +0000 UTC
    enqueued: 2021-01-08 19:09:26 +0000 UTC
    started: 2021-01-08 19:09:31 +0000 UTC

We'll need to update the action to handle this deprecation.