Bump actions/checkout in /.github/workflows in the actions group

Bumps the actions group in /.github/workflows with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `actions/checkout` from 4 to 5
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

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

@@ -11,7 +11,7 @@ jobs:
       runs-on: ubuntu-latest
 
       steps:
-        - uses: actions/checkout@v4
+        - uses: actions/checkout@v5
         - name: Set up Python
           uses: actions/setup-python@v5
           with:

.github/workflows/pytest.yml

@@ -18,7 +18,7 @@ jobs:
         python-version: ["3.11", "3.13"]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5
       with: