Changed basic image name for py_tools_ds_ci.docker.

tests/CI_docker/context/conda_pyenv.docker

@@ -14,6 +14,7 @@ RUN /bin/bash -i -c "cd /root; wget https://repo.continuum.io/miniconda/$minicon
 # copy some needed stuff to /root
 COPY *.yml /root/
 
+# create an environment with all packages specified in $envconfig
 RUN /bin/bash -i -c "source /root/miniconda3/bin/activate ; \
     conda env create -n $envname -f /root/$envconfig"
 

tests/CI_docker/context/py_tools_ds_ci.docker

-FROM conda_pyenv:latest
+FROM conda_pyenv