Bump actions/checkout from 4 to 5

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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/CI.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Install matplotlib
         run: if [ "$RUNNER_OS" = "Linux" ]; then sudo apt-get install -y python3-matplotlib; export PYTHON=$PYTHON_PATH; fi
         shell: bash
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}
@@ -54,7 +54,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 40
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: julia-actions/setup-julia@v2
       - uses: julia-actions/cache@v2
       - uses: julia-actions/julia-buildpkg@v1