feat: add GH action for closing stale prs and issues (#961)

* feat: add GH action for closing stale prs and issues

Signed-off-by: Diana Lease <dianarlease@gmail.com>

* feat: exempt anything in v4.0 milestone from being closed

Signed-off-by: Diana Lease <dianarlease@gmail.com>

---------

Signed-off-by: Diana Lease <dianarlease@gmail.com>

.github/workflows/close-stale.yml

@@ -0,0 +1,17 @@
+name: 'Close stale issues and PRs'
+on:
+  schedule:
+    - cron: '30 1 * * *'
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v9
+        with:
+          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 10 days.'
+          stale-pr-message: 'This PR is stale because it has been open 15 days with no activity. Remove stale label or comment or this will be closed in 10 days.'
+          days-before-issue-stale: 60
+          days-before-pr-stale: 15
+          days-before-close: 10
+          exempt-milestones: 'v4.0'