Bump actions/checkout from 3.5.3 to 4.0.0 in /.github/workflows

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.5.3 to 4.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3.5.3...v4.0.0)

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

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

.github/workflows/tests.yml

@@ -33,7 +33,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v3.5.3
+      - uses: actions/checkout@v4.0.0
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/[email protected]
         with: