fix ci not using the python version from the matrix

Author: DetachHead

.github/workflows/check and publish.yaml

@@ -22,6 +22,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python_version }}
+      - run: ./pw uv python pin ${{ matrix.python_version }}
       - run: ./pw uv sync
       - run: ./pw uv add robotframework==${{ matrix.robot_version }}
         if: ${{ matrix.robot_version != 'from lockfile' }}