Bump stefanzweifel/git-auto-commit-action from 4.14.1 to 4.15.4 (#487)

Bumps [stefanzweifel/git-auto-commit-action](https://github.com/stefanzweifel/git-auto-commit-action) from 4.14.1 to 4.15.4.
- [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@v4.14.1...v4.15.4)

.github/workflows/delete-preview.yml

@@ -12,7 +12,7 @@ jobs:
         with:
           ref: gh-pages
       - run: rm -rf previews/PR${{ github.event.number }}
-      - uses: stefanzweifel/git-auto-commit-action@v4.14.1
+      - uses: stefanzweifel/git-auto-commit-action@v4.15.4
         with:
           commit_message: 'Delete preview of PR#${{ github.event.number }}'
           branch: gh-pages