move probot stale.yml back to ./github

.github/workflows/stale.yml

@@ -1,18 +0,0 @@
-# Number of days of inactivity before an issue becomes stale
-daysUntilStale: 14
-# Number of days of inactivity before a stale issue is closed
-daysUntilClose: 3
-# Issues with these labels will never be considered stale
-exemptLabels:
-  - 'A: By design'
-  - 'A: In progress'
-  - 'A: Problematic'
-# Label to use when marking an issue as stale
-staleLabel: "A: Won't fix"
-# Comment to post when marking an issue as stale. Set to `false` to disable
-markComment: >
-  This issue has been automatically marked as stale because it has not had
-  recent activity. It will be closed if no further activity occurs. Thank you
-  for your contributions.
-# Comment to post when closing a stale issue. Set to `false` to disable
-closeComment: false