Add exempt-pr-labels for PRs

Author: seratch

.github/workflows/issues.yml

@@ -22,6 +22,7 @@ jobs:
           days-before-pr-stale: 10
           days-before-pr-close: 7
           stale-pr-label: "stale"
+          exempt-pr-labels: "skip-stale"
           stale-pr-message: "This PR is stale because it has been open for 10 days with no activity."
           close-pr-message: "This PR was closed because it has been inactive for 7 days since being marked as stale."
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          repo-token: ${{ secrets.GITHUB_TOKEN }}