Upgrde GitHuab Action for setup-python from v5 to v6 (#1506)

Author: tleonhardt

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
         uses: astral-sh/setup-uv@v6
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
           allow-prereleases: true