update ci with test doc (#1054)

.github/workflows/test.yml

@@ -35,6 +35,15 @@ jobs:
         pip install numpy==1.19.5 ruamel.yaml
         pip install pyqlib --ignore-installed
 
+    - name: Make html with sphnix
+      run: |
+        pip install -U sphinx
+        pip install sphinx_rtd_theme readthedocs_sphinx_ext
+        pip install --exists-action=w --no-cache-dir -r docs/requirements.txt 
+        cd docs 
+        sphinx-build -b html . build
+        cd ..
+        
     # Check Qlib with pylint
     # TODO: These problems we will solve in the future. Important among them are: W0221, W0223, W0237, E1102
       # C0103: invalid-name