[build][hotfix] Allow pinning issues & PRs that never decay

This closes #3816

Author: yuxiqian

.github/workflows/close_stale.yml

@@ -53,4 +53,7 @@ jobs:
           # Auto-remove stale has conflicts with existing approve label workflows
           # and will result in Stale label missing.
           remove-pr-stale-when-updated: false
-          remove-issue-stale-when-updated: false
+          remove-issue-stale-when-updated: false
+          # Allow pinning issues and PRs that is not meant to be closed automatically
+          exempt-issue-labels: "pinned"
+          exempt-pr-labels: "pinned"