Try setup-uv action for real real.

Author: stefanholek

.github/workflows/python-package.yml

@@ -36,7 +36,8 @@ jobs:
         uses: astral-sh/setup-uv@v9.0.0
         with:
           python-version: ${{ matrix.python-version }}
-          cache: auto
+          activate-environment: true
+          enable-cache: auto
 
       - name: Install dependencies
         run: uv pip install -e .