Add stale workflow.

.github/workflows/stale.yml

@@ -0,0 +1,28 @@
+name: Stale
+
+on:
+  issues:
+   types: [reopened]
+  schedule:
+   - cron: "*/60 * * * *"
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+    env:
+      ACTIONS_STEP_DEBUG: true
+    steps:
+    - uses: actions/stale@v3.0.10
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-issue-message: 'This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.'
+        stale-pr-message: 'This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.'
+        stale-issue-label: 'stale'
+        stale-pr-label: 'stale'
+        days-before-stale: 7
+        days-before-close: 2
+        exempt-issue-labels: 'discussion,help wanted,long running'
+        exempt-pr-labels: 'awaiting-approval,work-in-progress'
+        remove-stale-when-updated: true
+