ci: switch to reusable worfklow to handle stale issues (#212)

Fixes #176

Author: afuetterer

.github/workflows/stale.yml

@@ -1,34 +1,17 @@
-# Ref: https://github.com/actions/stale
 name: Handle stale issues and PRs
 
 on:
   schedule:
-    # run once a week at midnight of sunday
-  - cron: 0 0 * * 0
+    # run once a month at midnight of the first day of the month
+  - cron: 0 0 1 * *
   workflow_dispatch: # run manually from actions tab
 
 # Set permissions at the job level.
 permissions: {}
 
 jobs:
   stale:
-    runs-on: ubuntu-24.04
     permissions:
       issues: write
       pull-requests: write
-    steps:
-    - uses: actions/stale@28ca1036281a5e5922ead5184a1bbf96e5fc984e # v9.0.0
-      with:
-        days-before-stale: 60
-        # handle issues: set to abandoned, close after 7 days with message
-        days-before-issue-close: 7
-        stale-issue-label: 'status: abandoned'
-        stale-issue-message: |
-          This issue is stale because it has been open 60 days without activity.
-          Remove 'abandoned' 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.
-
-        # handle pull requests: set to abandoned, but do not close per bot
-        days-before-pr-close: -1 # never close PRs
-        stale-pr-label: 'status: abandoned'
-        stale-pr-message: This PR is stale because it has been open 60 days without activity.
+    uses: afuetterer/.github/.github/workflows/_stale.yml@main