Bump actions/checkout from 3 to 4

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]>

.github/workflows/ci-tests.yml

@@ -40,7 +40,7 @@ jobs:
         name: "Python: ${{ matrix.py }}-${{ matrix.architecture }} on ${{ matrix.os }}"
         runs-on: ${{ matrix.os }}
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@v4
             - name: Setup python
               uses: actions/setup-python@v4
               with:
@@ -53,7 +53,7 @@ jobs:
         runs-on: ubuntu-latest
         name: Validate coverage
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@v4
             - name: Setup python 3.9
               uses: actions/setup-python@v4
               with:
@@ -65,7 +65,7 @@ jobs:
         runs-on: ubuntu-latest
         name: Build the documentation
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@v4
             - name: Setup python
               uses: actions/setup-python@v4
               with:
@@ -77,7 +77,7 @@ jobs:
         runs-on: ubuntu-latest
         name: Lint the package
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@v4
             - name: Setup python
               uses: actions/setup-python@v4
               with: