Apply suggestions from code review

Author: Borda

Dockerfile.tmpl

@@ -171,7 +171,7 @@ RUN pip install pysal \
         seaborn python-dateutil dask python-igraph \
         pyyaml joblib husl geopy mne pyshp \
         pandas \
-        flax \
+        flax && \
     # Install h2o from source.
     # Use `conda install -c h2oai h2o` once Python 3.7 version is released to conda.
     apt-get install -y default-jre-headless && \