Bump actions/stale from 5 to 6 (#114)

Bumps [actions/stale](https://github.com/actions/stale) from 5 to 6.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](actions/stale@v5...v6)

.github/workflows/stale-close.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Close stale issues & pull requests
-        uses: actions/stale@v5
+        uses: actions/stale@v6
         with:
           days-before-stale: 60
           days-before-close: 7