update docker setup for new docker version pip cmake

Buildserver/Dockerfile_setup

@@ -15,4 +15,4 @@ RUN apt-get update && apt-get install -y libmpich-dev
 
 # Install also Python 3
 RUN apt-get update && apt-get install -y python3
-RUN python3 -m pip install cmake
+RUN pip3 install cmake