Bump actions/setup-python from 3 to 4 (#300)

* Bump actions/setup-python from 3 to 4

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 3 to 4.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v3...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>

* State the Python version explictly

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Martijn Pieters <mj@zopatista.com>

.github/workflows/ci.yml

@@ -23,7 +23,9 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3.x
     - name: Cache PyPI
       uses: actions/cache@v3
       with:
@@ -84,7 +86,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python ${{ matrix.pyver }}
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.pyver }}
     - name: Get pip cache dir
@@ -154,7 +156,9 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3.x
     - name: Install cython
       uses: py-actions/py-dependency-install@v3
       with:
@@ -205,7 +209,9 @@ jobs:
         fi
       shell: bash
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3.x
     - name: Install cython
       uses: py-actions/py-dependency-install@v3
       with: