Merge pull request #1349 from firebase/fix-stale-naming-in-action

Fix stale naming

Author: demolaf

.github/workflows/stale-issue.yml

@@ -39,4 +39,4 @@ jobs:
           days-before-stale: 28
           days-before-close: 15
           stale-issue-label: 'not-planned'
-          stale-pr-label: 'Stale'
+          stale-pr-label: 'stale'