Create stale.yml

.github/workflows/stale.yml

@@ -0,0 +1,16 @@
+name: "Close stale issues"
+
+on:
+  schedule:
+  - cron: "6 6 * * *"
+
+jobs:
+  stale:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/stale@v1
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-issue-message: 'This issue is stale because it has been open 21 days with no activity. Remove stale label or comment or this will be closed in 7 days.'
+        days-before-stale: 21
+        days-before-close: 7