ci: use uv for generating Sphinx docs

.github/workflows/sphinx.yml

@@ -5,16 +5,18 @@ on:
     - cron: '30 13 * * *'
 jobs:
   sphinx:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - name: Install uv
+        uses: astral-sh/setup-uv@v3
         with:
-          python-version: '3.11'
+          version: "0.4.29"
       - name: Run Sphinx
         run: |
-          python -m pip install -r ci/requirements.txt
-          python -m pip install --config-settings=--build-option=--no-c-backend .
-
-          python -m pip install Sphinx==5.3.0
+          uv venv --python 3.12 venv
+          source venv/bin/activate
+          uv pip install -r ci/requirements.txt
+          uv pip install --config-settings=--build-option=--no-c-backend .
+          uv pip install Sphinx==5.3.0
           make -C docs html