Bump actions/deploy-pages from 2 to 4

Bumps [actions/deploy-pages](https://github.com/actions/deploy-pages) from 2 to 4.
- [Release notes](https://github.com/actions/deploy-pages/releases)
- [Commits](actions/deploy-pages@v2...v4)

---
updated-dependencies:
- dependency-name: actions/deploy-pages
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/deploy-book.yml

@@ -57,4 +57,4 @@ jobs:
     # Deploy the book's HTML to GitHub Pages
     - name: Deploy to GitHub Pages
       id: deployment
-      uses: actions/deploy-pages@v2
+      uses: actions/deploy-pages@v4