Bump actions/checkout from 3.5.3 to 4.0.0

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] <support@github.com>

.github/workflows/main.yaml

@@ -29,7 +29,7 @@ jobs:
     steps:
       # Checkout current git repository
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4.0.0
         with:
           # fetch all history so that setuptools-scm works
           fetch-depth: 0