Bump actions/setup-python from 2 to 4

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 2 to 4.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v2...v4)

---
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/ci.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: "3.X"
     - name: Install dependencies
@@ -62,7 +62,7 @@ jobs:
       with:
         fetch-depth: 0
     - name: Set up Python
-      uses: actions/setup-python@v4.3.1
+      uses: actions/setup-python@v4
       with:
         python-version: "3.9"
     - name: Install system dependencies