Dockerfiles: remove workaround for grass-session (#1624)

Partial revert of #1623

docker/alpine/Dockerfile_alpine

@@ -192,10 +192,6 @@ RUN apk add curl && curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py && p
 
 # install external Python API
 RUN pip3 install --upgrade pip six grass-session --ignore-installed six
-# GRASS GIS 8 version workaround, awaiting grass-session update
-RUN sed -i 's+\.grass7+\.grass8+g' /usr/lib/python3.?/site-packages/grass_session/*.py
-RUN sed -i 's+grass7+grass+g' /usr/local/lib/python3.?/site-packages/grass_session/*.py
-RUN sed -i 's+GRASS7+GRASS8+g' /usr/local/lib/python3.?/site-packages/grass_session/*.py
 
 RUN ln -sf `grass --config path` /usr/local/grass
 RUN grass --tmp-location EPSG:4326 --exec g.version -rge && \

docker/debian/Dockerfile_debian_pdal

@@ -226,10 +226,6 @@ WORKDIR /scripts
 
 # install external GRASS GIS session Python API
 RUN pip3 install grass-session
-# GRASS GIS 8 version workaround, awaiting grass-session update
-RUN sed -i 's+\.grass7+\.grass8+g' /usr/lib/python3.?/site-packages/grass_session/*.py
-RUN sed -i 's+grass7+grass+g' /usr/local/lib/python3.?/site-packages/grass_session/*.py
-RUN sed -i 's+GRASS7+GRASS8+g' /usr/local/lib/python3.?/site-packages/grass_session/*.py
 
 # install GRASS GIS extensions
 RUN grass --tmp-location EPSG:4326 --exec g.extension extension=r.in.pdal

docker/ubuntu/Dockerfile_ubuntu_pdal

@@ -218,10 +218,6 @@ WORKDIR /scripts
 
 # install external GRASS GIS session Python API
 RUN pip3 install grass-session
-# GRASS GIS 8 version workaround, awaiting grass-session update
-RUN sed -i 's+\.grass7+\.grass8+g' /usr/lib/python3.?/site-packages/grass_session/*.py
-RUN sed -i 's+grass7+grass+g' /usr/local/lib/python3.?/site-packages/grass_session/*.py
-RUN sed -i 's+GRASS7+GRASS8+g' /usr/local/lib/python3.?/site-packages/grass_session/*.py
 
 # install GRASS GIS extensions
 RUN grass --tmp-location EPSG:4326 --exec g.extension extension=r.in.pdal