Introduce stale workflow

Use this link to re-run the recipe: https://app.moderne.io/builder/ITGQhdQKv?organizationId=T3BlblJld3JpdGU%3D

Co-authored-by: Moderne <[email protected]>

Author: greg-at-moderne

.github/workflows/stale.yml

@@ -0,0 +1,11 @@
+---
+name: stale
+
+on:
+  workflow_dispatch: {}
+  schedule:
+    - cron: 36 4 * * 1
+
+jobs:
+  build:
+    uses: openrewrite/gh-automation/.github/workflows/stale.yml@main