Create symbolic link to make sure Python 3 can be called with python

Dockerfile

@@ -8,6 +8,7 @@ LABEL com.example.vendor="LakeDrops" \
 
 RUN apt-get update -y && \
     apt-get install -y -q python3 make g++ && \
+    ln -s python3 /usr/bin/python && \
     \
     apt-get clean && \
     rm -rf /root/.cache && \