:robot: Adds Stale GitHub Action to keep things fresh

Thank you @lorenanicole and @pyladies for the inspiration.

https://github.com/pyladies/chapter-websites/blob/main/.github/workflows/stale.yml

.github/worksflows/stale.yml

@@ -0,0 +1,21 @@
+name: Mark stale issues and pull requests
+
+on:
+  schedule:
+  - cron: "0 0 * * *"
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/stale@v1
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-issue-message: 'This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 5 days'
+        stale-pr-message: 'This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 5 days'
+        stale-issue-label: 'no-issue-activity'
+        stale-pr-label: 'no-pr-activity'
+        days-before-stale: 60
+        days-before-close: 5