Bump actions/checkout from 3 to 4 (#1914)

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](https://github.com/actions/checkout/compare/v3...v4)

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

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

.github/workflows/docker.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # Add support for more platforms with QEMU (optional)
       # https://github.com/docker/setup-qemu-action

.github/workflows/tox.yml

@@ -23,7 +23,7 @@ jobs:
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12.0-rc.1", "pypy-3.9", "pypy-3.10"]
     continue-on-error: ${{ matrix.python-version == '3.12.0-rc.1' }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with: