Meta: use org-wide stale bot config (#1789)

.github/stale.yml

@@ -1,23 +1 @@
-limitPerRun: 30
-daysUntilStale: 30
-daysUntilClose: 7
-
-exemptLabels:
-  - pinned
-  - security
-  - "[Status] Maybe Later"
-
-exemptAssignees: true
-
-staleLabel: wontfix
-
-pulls:
-  markComment: >
-    This pull request 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.
-issues:
-  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.
+_extends: .github