Bump actions/checkout from 2 to 5

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/book.yml

@@ -12,7 +12,7 @@ jobs:
         sudo apt-get -yq update
         sudo apt-get install -yq pandoc texlive-xetex texlive-fonts-extra gfortran ffmpeg
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v5
     - name: Install Miniconda
       uses: conda-incubator/setup-miniconda@v2
       with: