Switch from probot/stale to actions/stale

[bmw]

Our stale bot seems to be broken and deprecated. See probot/stale#385. I think we should uninstall our current stale bot and set up https://github.com/marketplace/actions/close-stale-issues.

Our current stale bot config can be found at https://github.com/certbot/certbot/blob/master/.github/stale.yml.

[bmw]

I wanted to check in on the status of things here. It looks like we're still setting debug-only:

certbot/.github/workflows/stale.yml

Lines 14 to 15 in dc07dfd

	# REMOVEME: dry run to see if this works
	debug-only: true

Do we need to do anything before we remove that? I opened a PR to fix the only thing that looked strange to me in the run history at #9577.

[wgreenberg]

ah yes, i'd left the debug flag on while debugging why we weren't seeing any issues in the dry-run output, but that seems to be fixed w/ the operations # change. i think we're probably good to remove the dry-run flag now!