CI: deploy website to different repo

Currently, GitHub Pages sources https://quick-lint-js.com/ from the
gh-pages branch of the https://github.com/quick-lint/quick-lint-js repo.
The gh-pages branch slows down 'git clone' for new contributors.

Switch deployment to the master branch of the new
https://github.com/quick-lint/quick-lint-js.com repo. I already
configured GitHub Pages to source https://quick-lint-js.com/ from this
new repo.

Author: strager

.github/workflows/deploy-website.yml

@@ -30,10 +30,11 @@ jobs:
         uses: peaceiris/actions-gh-pages@v3
         with:
           cname: quick-lint-js.com
+          external_repository: quick-lint/quick-lint-js.com
           full_commit_message: "Website: deploy build ${{ github.event.inputs.build_commit_id }} source ${{ github.sha }}"
-          github_token: ${{ secrets.GITHUB_TOKEN }}
           keep_files: false
-          publish_branch: gh-pages
+          personal_token: ${{ secrets.QUICK_LINT_JS_COM_PERSONAL_ACCESS_TOKEN }}
+          publish_branch: master
           publish_dir: ./website/www
 
 # quick-lint-js finds bugs in JavaScript programs.