Switch stale-bot implementation (#146)

Fixes #145

.github/workflows/stale-bot.yml

@@ -0,0 +1,29 @@
+name: 'Stale-Bot'
+on:
+  schedule:
+    - cron: '30 1 * * *'
+
+# see https://github.com/actions/stale
+
+permissions:
+  contents: write
+  issues: write
+  pull-requests: write
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v7
+        with:
+          stale-issue-label: stale
+          stale-pr-label: stale
+          stale-issue-message: 'This issue is stale because it has 60 days with no activity. Remove stale label or comment or this will be closed in 7 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 7 days.'
+          close-issue-message: 'This issue was closed because it has been stalled for 7 days with no activity.'
+          days-before-stale: 60
+          days-before-close: 7
+          close-issue-reason: stale
+          close-issue-label: stale
+          exempt-issue-labels: idea
+          exempt-pr-labels: idea