add stale issue bot

Author: Christopher Doris

.github/workflows/stale.yaml

@@ -0,0 +1,31 @@
+name: 'Close stale issues and PRs'
+on:
+  schedule:
+    - cron: '30 1 * * *'
+permissions:
+  issues: write
+  pull-requests: write
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v8
+        with:
+          days-before-issue-stale: 60
+          stale-issue-message: >
+            This issue has been marked as stale because it has been open for 60 days with no
+            activity. If the issue is still relevant then please leave a comment, or else it
+            will be closed in 7 days.
+          days-before-pr-stale: 60
+          stale-pr-message: >
+            Thank you for your pull request. It has been marked as stale because it has been
+            open for 60 days with no activity. If the PR is still relevant then please leave
+            a comment, or else it will be closed in 30 days.
+          days-before-issue-close: 7
+          close-issue-message: >
+            This issue has been closed because it has been stale for 7 days. You can re-open
+            it if it is still relevant.
+          days-before-pr-close: 30
+          close-pr-message: >
+            This PR has been closed because it has been stale for 30 days. You can re-open
+            it if it is still relevant.