Bump actions/checkout from 3 to 4 (#152)

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

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
         --user
         tox
     - name: Check out src from Git
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         fetch-depth: 0  # needed by setuptools-scm
     - name: Build dists

.github/workflows/tox.yml

@@ -34,7 +34,7 @@ jobs:
       matrix: ${{ fromJson(needs.pre.outputs.matrix) }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0  # needed by setuptools-scm