gha: fix nox envs cache keys

Author: dtrifiro

.github/workflows/tests.yaml

@@ -76,7 +76,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: /home/runner/.nox
-          key: ${{ runner.os }}-python-${{steps.setup-python.outputs.python-version }}-${{ hashFiles('noxfile.py') }}
+          key: ${{ runner.os }}-python-${{matrix.pyv}}-${{ hashFiles('noxfile.py') }}-${{matrix.vllm_version}}
 
       - name: Lint code and check dependencies
         run: nox --envdir ~/.nox --reuse-venv=yes -v -s lint-${{ matrix.pyv }}