chore(ci): label stale PRs and clean its cache #1127

	# based on https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#managing-caches

	name: Cleanup caches by a branch
	on:
	pull_request:
	types:
	- closed
	- labeled

	jobs:
	cleanup:
	runs-on: ubuntu-latest
	steps:
	- name: Cleanup
	# when the PR is closed or labeled as 'Stale'
	if: ${{ github.event.action == 'closed' \|\| github.event.label.name == 'Stale' }}
	run: \|
	gh extension install actions/gh-actions-cache

	echo "Fetching list of cache key"
	cacheKeysForPR=$(gh actions-cache list -R $REPO -B $BRANCH -L 100 \| cut -f 1 )

	## Setting this to not fail the workflow while deleting cache keys.
	set +e
	echo "Deleting caches..."
	for cacheKey in $cacheKeysForPR
	do
	gh actions-cache delete $cacheKey -R $REPO -B $BRANCH --confirm
	done
	echo "Done"
	env:
	GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
	REPO: ${{ github.repository }}
	BRANCH: refs/pull/${{ github.event.pull_request.number }}/merge

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