Update to grass-session v0.5

docker/ubuntu/Dockerfile_ubuntu_pdal

@@ -226,10 +226,7 @@ RUN apt-get clean -y
 WORKDIR /scripts
 
 # install external GRASS GIS session Python API
-#RUN pip3 install grass-session
-# ugly workaround for https://github.com/zarch/grass-session/issues/16
-RUN apt-get install git
-RUN pip3 install --upgrade pip3 git+git://github.com/zarch/grass-session.git@0b8414c1
+RUN pip3 install grass-session
 
 # install GRASS GIS extensions
 RUN grass --tmp-location EPSG:4326 --exec g.extension extension=r.in.pdal