Set up Python in CI workflow

Add a setup-python step to the check workflow using actions/setup-python@v6. The step uses the matrix.python-version and enables pip caching so the subsequent 'pip install -e ".[dev]"' runs with the correct interpreter and faster dependency installs.

Author: YaronKoresh

.github/workflows/check.yml

@@ -17,6 +17,12 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+
       - name: Install Dev Tools
         run: pip install -e ".[dev]"