Allow certain labels on a PR to exempt it from going stale (#15922)

.github/workflows/stale.yml

@@ -2,7 +2,7 @@
 # A PR with more than 60 days of inactivity will be marked as stale
 # A PR that's stale for more than 7 days will be automatically closed
 # Issues are exempt from auto marking as stale but issues with manually added 'stale' label are eligible for auto closure after 7 days.
-# PRs with assignees are exempt from auto stale marking, it's the responsibility of the assignee to get the PR progressed either with review/merge or closure.
+# PRs with `exempt-pr-labels` or assignees are exempt from auto stale marking, it's the responsibility of the assignee to get the PR progressed either with review/merge or closure.
 name: Manage stale Issues and PRs
 
 on:
@@ -11,16 +11,17 @@ on:
 
 jobs:
   stale:
-
     runs-on: ubuntu-latest
     permissions:
       issues: write
       pull-requests: write
 
     steps:
-    - uses: actions/[email protected]
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        exempt-all-pr-assignees: true
-        stale-pr-message: 'This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days.'
-        days-before-issue-stale: -1 # disables marking issues as stale automatically. Issues can still be marked as stale manually, in which the closure policy applies.
+      - uses: actions/[email protected]
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          exempt-all-pr-assignees: true
+          stale-pr-message: "This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days."
+          days-before-issue-stale: -1 # disables marking issues as stale automatically. Issues can still be marked as stale manually, in which the closure policy applies.
+          # Comma separated list of labels that exempt issues from being considered stale.
+          exempt-pr-labels: "stale-exempt"