Update building_turbine_ig.yml

.github/workflows/building_turbine_ig.yml

@@ -28,8 +28,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install sphinx
-        pip install sphinx-rtd-theme
+        pip install -r ../requirements.txt
 
     - name: Build documentation
       run: |