python_client_example build fails

[vbachurin]

Docker Engine: 19.03.13
Docker Compose: 1.27.4
macOs Catalina 10.15.7

https://github.com/jupyter/kernel_gateway_demos/tree/master/python_client_example

$ docker-compose up
...
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-1xaw773u/argon2-cffi
You are using pip version 7.1.2, however version 20.2.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

Fix/workaround:
Use latest Docker image instead of

FROM jupyter/all-spark-notebook:0017b56d93c9

in https://github.com/jupyter/kernel_gateway_demos/blob/master/python_client_example/Dockerfile.kg#L5

[kevin-bates]

Hi Vlad - thanks for pointing this out. Given the lack of traffic to these demos, I would agree that it's probably best we keep things more dynamic and move to referencing the 'latest' tag even though this isn't necessarily recommended from a reproducibility standpoint.

It would be great if you could contribute this change. Thank you.