Try to fix building docs in GH Action

Author: hongquan

.github/workflows/build.yml

@@ -55,10 +55,10 @@ jobs:
         run: |
           sudo apt -y update
           sudo apt -y install gcc libsystemd-dev universal-ctags
-          python -m pip install --break-system-packages pytest sphinx build
 
       - name: Build (Python ${{ matrix.python }})
         run: |
           set -x
           uv build -C build-dir=_build
+          uv sync --no-editable --group docs
           cd _build && uv run --group docs --no-editable -m sphinx -b html -W -v ../docs html