Bump actions/stale from 3 to 8 (#10)

Bumps [actions/stale](https://github.com/actions/stale) from 3 to 8.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](actions/stale@v3...v8)

---
updated-dependencies:
- dependency-name: actions/stale
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/stale.yml

@@ -9,7 +9,7 @@ jobs:
  stale:
  runs-on: ubuntu-latest
  steps:
- - uses: actions/stale@v3
+ - uses: actions/stale@v8
  with:
  repo-token: ${{ secrets.GITHUB_TOKEN }}
  stale-issue-message: 'Stale issue message'