ci: bump stefanzweifel/git-auto-commit-action from 4 to 5 (#5)

Bumps [stefanzweifel/git-auto-commit-action](https://github.com/stefanzweifel/git-auto-commit-action) from 4 to 5.
- [Release notes](https://github.com/stefanzweifel/git-auto-commit-action/releases)
- [Changelog](https://github.com/stefanzweifel/git-auto-commit-action/blob/master/CHANGELOG.md)
- [Commits](stefanzweifel/git-auto-commit-action@v4...v5)

---
updated-dependencies:
- dependency-name: stefanzweifel/git-auto-commit-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/update-firefox-addons.yml

@@ -22,7 +22,7 @@ jobs:
       - env:
           NIXPKGS_ALLOW_UNFREE: "1"
         run: nix develop --impure -c mozilla-addons-to-nix pkgs/firefox-addons/firefox-addons.json pkgs/firefox-addons/default.nix
-      - uses: stefanzweifel/git-auto-commit-action@v4
+      - uses: stefanzweifel/git-auto-commit-action@v5
         with:
           commit_message: "firefox-addons: update as of ${{ steps.metadata.outputs.DATE }}"
           file_pattern: pkgs/firefox-addons/