Docker build command fails on python tutorial page

[josros]

Execution

Start a terminal and execute the docker build command stated in Step 1 of the python tutorial:

docker build \
    --build-arg language=python \
    -t snet_python_service https://github.com/singnet/dev-portal.git#master:/tutorials/docker

Expectation

The docker build command succeeds and I have a ready to start docker image on my computer

Actual behaviour

The docker build fails at step [5/11]:

 => [ 4/11] RUN apt-get install -y python3 python3-pip                    15.5s
 => ERROR [ 5/11] RUN pip3 install snet-cli                                9.5s

9.438 protobuf requires Python '>=3.7' but the running Python is 3.6.9
------
Dockerfile:25
--------------------
  23 |     RUN apt-get install -y python3 python3-pip
  24 |     
  25 | >>> RUN pip3 install snet-cli
  26 |     
  27 |     RUN SNETD_VERSION=`curl -s https://api.github.com/repos/singnet/snet-daemon/releases/latest | grep -oP '"tag_name": "\K(.*)(?=")'` && \
--------------------
ERROR: failed to solve: process "/bin/sh -c pip3 install snet-cli" did not complete successfully: exit code: 1

Workaround

I used a local copy of the Dockerfile and changed:

RUN apt-get install -y python3 python3-pip

RUN pip3 install snet-cli

to:

RUN apt-get install -y python3 python3-pip

RUN pip3 install --upgrade pip && \
    pip3 install snet-cli

This way I was able to follow the tutorial up until Step 8. However, it leaded to maybe related error scenarios such as the problem that I could not execute snet organization metadata-init and others.
Maybe it is because the the python version and base image ubuntu:18.04 are outdated.