Bump purcell/setup-emacs from 5.0 to 6.0 (#11)

Bumps [purcell/setup-emacs](https://github.com/purcell/setup-emacs) from 5.0 to 6.0.
- [Release notes](https://github.com/purcell/setup-emacs/releases)
- [Commits](purcell/setup-emacs@v5.0...v6.0)

---
updated-dependencies:
- dependency-name: purcell/setup-emacs
  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/jekyll.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: purcell/setup-emacs@v5.0
+      - uses: purcell/setup-emacs@v6.0
         with:
           version: 28.1
       - name: Run Emacs Org mode publish to convert Org mode files to HTML