chore(deps): update astral-sh/setup-uv action to v6 (#20)

Author: renovate[bot]

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-      - uses: astral-sh/setup-uv@v5
+      - uses: astral-sh/setup-uv@v6
       - run: uv pip install --system tox tox-uv
         shell: bash
       - run: tox -f py$(echo ${{ matrix.python-version }} | tr -d .)