[BEAM-4423] Mark pull requests stale after 60 days; close 7 days after warning

.github/stale.yml

@@ -0,0 +1,27 @@
+# Configuration for probot-stale - https://github.com/probot/stale
+
+# Issues or Pull Requests with these labels will never be considered stale. Set to `[]` to disable
+exemptLabels:
+  - pinned
+  - security
+
+# Limit to only `issues` or `pulls`
+only: pulls
+
+# Configuration settings that are specific to just 'issues' or 'pulls':
+pulls:
+  daysUntilStale: 60
+  daysUntilClose: 7
+  markComment: >
+    This pull request has been marked as stale due to 60 days of inactivity.
+    It will be closed in 1 week if no further activity occurs. If you think
+    that’s incorrect or this pull request requires a review, please simply
+    write any comment. If closed, you can revive the PR at any time and @mention
+    a reviewer or discuss it on the dev@beam.apache.org list.
+    Thank you for your contributions.
+  unmarkComment: >
+    This pull request is no longer marked as stale.
+  closeComment: >
+    This pull request has been closed due to lack of activity. If you think that
+    is incorrect, or the pull request requires review, you can revive the PR at
+    any time.