Bump actions/checkout from 6 to 7

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci-tests.yml

@@ -83,7 +83,7 @@ jobs:
     name: "Python: ${{ matrix.py }}-${{ matrix.architecture }} on ${{ matrix.os }}"
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Setup python
         uses: actions/setup-python@v6
         with:
@@ -103,7 +103,7 @@ jobs:
     runs-on: ubuntu-22.04
     name: Validate coverage
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Setup python
         uses: actions/setup-python@v6
         with:
@@ -116,7 +116,7 @@ jobs:
     runs-on: ubuntu-22.04
     name: Build the documentation
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Setup python
         uses: actions/setup-python@v6
         with:
@@ -129,7 +129,7 @@ jobs:
     runs-on: ubuntu-22.04
     name: Lint the package
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Setup python
         uses: actions/setup-python@v6
         with: