Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

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

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

.github/workflows/book-weekly.yml

@@ -27,7 +27,7 @@ jobs:
         run: quarto tools install chromium
 
       - name: Cache R packages
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/R/renv
           key: ${{ runner.os }}-r-${{ steps.setup.outputs.installed-r-version }}-weekly-lock-${{ hashFiles('book/renv.lock') }}
@@ -49,7 +49,7 @@ jobs:
           R -q -e 'renv::update(prompt = FALSE)'
 
       - name: Cache OpenML
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         id: openml-cache
         with:
           path: book/openml

.github/workflows/build-book.yml

@@ -31,7 +31,7 @@ jobs:
         run: quarto tools install chromium
 
       - name: Cache R packages
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/R/renv
           key: ${{ runner.os }}-r-${{ steps.setup.outputs.installed-r-version }}-lock-${{ hashFiles('book/renv.lock') }}
@@ -48,7 +48,7 @@ jobs:
           R -q -e 'options(Ncpus = 2); install.packages("renv", repos = "cloud.r-project.org"); renv::restore()'
 
       - name: Cache OpenML
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         id: openml-cache
         with:
           path: book/openml