.github/workflows: Add a workflow for dealing with stale issues/prs

Author: the-maldridge

.github/workflows/stale.yml

@@ -0,0 +1,18 @@
+---
+name: Stale Cleanup
+
+on:
+  schedule:
+    - cron: '30 1 * * *'
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v4
+        with:
+          stale-issue-message: 'Issues become stale 90 days after last activity and are closed 7 days after that.  If this issue is still relevant bump it or assign it.'
+          stale-pr-message: 'Pull Requests become stale 90 days after last activity and are closed 7 days after that.  If this pull request is still relevant bump it or assign it.'
+          days-before-stale: 90
+          days-before-close: 7
+          debug-only: true