Bump actions/checkout from 3 to 4 (#628)

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/check-sphinx-and-links.yml

@@ -7,7 +7,7 @@ jobs:
   docs:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     # - uses: ammaraskar/sphinx-action@master
     # Using fork of sphinx-action to support python version > 3.9

.github/workflows/publish-to-pypi.yml

@@ -7,7 +7,7 @@ jobs:
     name: Build and publish Python 🐍 distributions 📦 to PyPI
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python 3.10
       uses: actions/[email protected]
       with:

.github/workflows/run-tests.yml

@@ -10,7 +10,7 @@ jobs:
       matrix:
         python: ['3.8', '3.9', '3.10', '3.11']
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python
       uses: actions/[email protected]
       with: