pipx: use correct version of Python

Author: stefanv

.github/workflows/test.yml

@@ -27,6 +27,7 @@ jobs:
       - uses: actions/checkout@v5
       - uses: actions/setup-python@v6
         with:
+          id: setup-python
           python-version: ${{ matrix.python_version }}
           allow-prereleases: true
           cache: "pip"
@@ -37,4 +38,4 @@ jobs:
           sudo apt-get install -y gdb lcov
       - name: Tests PyTest
         run: |
-          pipx run nox --forcecolor -s test
+          pipx run --python '${{ steps.setup-python.outputs.python-path }}' nox --forcecolor -s test