Exempt issues with "exempt-stale" from staling (#4385)

The exempt-stale label was not actually set to exempt issues from staling...

.github/workflows/stale.yml

@@ -16,7 +16,7 @@ jobs:
         days-before-stale: 365
         days-before-pr-stale: 90 
         days-before-close: 30
-        exempt-pr-labels: blocked
+        exempt-pr-labels: blocked,exempt-stale
         stale-issue-message: 'This issue has been automatically marked as stale and will be closed in 30 days because it has not had recent activity and is much likely outdated. If you think this issue is still relevant and applicable, you just have to post a comment and it will be unmarked.'
         stale-pr-message: 'This pull request has been automatically marked as stale and will be closed in 30 days because it has not had recent activity and is much likely abandoned or outdated. If you think this pull request is still relevant and applicable, you just have to post a comment and it will be unmarked.'
         stale-issue-label: "stale"