Bump actions/setup-python from 2 to 3

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 2 to 3.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v2...v3)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/pages.yml

@@ -17,7 +17,7 @@ jobs:
           fetch-depth: 10
 
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: 3.9
 

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python-version }}