update CI after update of python install process

.gitlab-ci.yml

@@ -132,7 +132,7 @@ gcc_9_python:
     - export CCACHE_DIR=$CI_PROJECT_DIR/cache
 
   script:
-    - python3 setup.py bdist_wheel build_ext --build-temp=build
+    - python3 setup.py bdist_wheel build_ext --build-temp=build -DBUILD_VF_CPU=ON
 
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 ##                            Container Upload                               ##

setup.py

@@ -7,8 +7,12 @@ import setuptools
 
 """
 Install python wrapper of virtual fluids
-install via python setup.py install build_ext
-set CMAKE Flags via -DBUILD_VF_GPU:BOOL=1
+install via python:
+    python setup.py install build_ext
+    set CMAKE Flags via -DBUILD_VF_GPU:BOOL=1
+or install via pip:
+    pip install -e .
+    set CMAKE Flags via --configure-settings -DBUILD_VF_GPU=1
 """
 
 init_py = inspect.cleandoc(