ci: add workflow for stale issues

.github/workflows/stale.yml

@@ -0,0 +1,43 @@
+name: Close stale issues and PRs
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: 30 1 * * *
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v8
+        with:
+          # Number of days of inactivity before an issue becomes stale
+          days-before-stale: 60
+
+          # Number of days of inactivity before a stale issue is closed
+          days-before-close: 14
+
+          # Label to use when marking an issue as stale
+          stale-issue-label: stale
+          stale-pr-label: stale
+
+          # Issues with these labels will never be considered stale
+          exempt-issue-labels: pinned,security,confirmed,planned
+          exempt-pr-labels: pinned,security,confirmed,planned,dependencies
+
+          stale-issue-message: >
+            This issue has been automatically marked as stale because it has not had
+            activity in the last 60 days. It will be closed in two weeks if no further activity
+            occurs. Thank you for your contributions.
+
+          close-issue-message: >
+            This issue has been automatically closed due to inactivity. If it
+            is still valid, please post a comment.
+
+          stale-pr-message: >
+            This pull request has been automatically marked as stale because it has not had
+            activity in the last 60 days. It will be closed in two weeks if no further activity
+            occurs. Thank you for your contributions.
+
+          close-pr-message: >
+            This pull request has been automatically closed due to inactivity. If it
+            is still valid, please post a comment.