Add workflow to mark issue/pr stale (#1273)

.github/workflows/stale.yaml

@@ -0,0 +1,32 @@
+---
+# https://github.com/actions/stale
+name: Close stale PRs & Issues
+on:  # yamllint disable-line rule:truthy
+  schedule:
+    - cron: '0 0 * * *'
+permissions:
+  pull-requests: write
+  issues: write
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v8
+        with:
+          stale-pr-message: >
+            This pull request has been automatically marked as stale because it has not had
+            recent activity. It will be closed in 15 days if no further activity occurs. Thank you
+            for your contributions.
+          days-before-pr-stale: 90
+          days-before-pr-close: 15
+          exempt-pr-labels: 'security'
+          only-issue-labels: 'pending-response'
+          remove-stale-when-updated: true
+          days-before-issue-stale: 180
+          days-before-issue-close: 15
+          stale-issue-message: >
+            This issue has been automatically marked as stale because it has been open for 30 days
+            with no response from the author. It will be closed in next 15 days if no further
+            activity occurs from the issue author.
+          close-issue-message: >
+            This issue has been closed because it has not received response from the issue author.