chore(deps): bump actions/stale from 6 to 9 (#20968)

Bumps [actions/stale](https://github.com/actions/stale) from 6 to 9.
- [Release notes](https://github.com/actions/stale/releases)
- [Changelog](https://github.com/actions/stale/blob/main/CHANGELOG.md)
- [Commits](actions/stale@v6...v9)

---
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.yaml

@@ -9,7 +9,7 @@ jobs:
         if: ${{ github.repository == 'PostHog/posthog' }}
         runs-on: ubuntu-latest
         steps:
-            - uses: actions/stale@v6
+            - uses: actions/stale@v9
               with:
                   days-before-issue-stale: 730
                   days-before-issue-close: 14