Bump actions/setup-python from 4 to 5 (#170)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 4 to 5.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v4...v5)

---
updated-dependencies:
- dependency-name: actions/setup-python
  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/release.yml

@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Switch to using Python 3.9 by default
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           cache: "pip"
           python-version: 3.9

.github/workflows/tox.yml

@@ -76,7 +76,7 @@ jobs:
           fetch-depth: 0 # needed by setuptools-scm
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           cache: "pip"
           python-version: ${{ matrix.python-version }}