docs: Simple python example

[gdanezis]

A simple python example using requests to upload and then download a file.

[karlwuest]

Nice short example!
One additional suggestion:
Even though there's only one non-std requirement, it would be nice to provide a requirements.txt or a poetry pyproject.toml or to at least put the pip install in the prerequisites.

[mlegner]

Thanks, @gdanezis, this works well with the latest version of Walrus.

Just a few minor suggestions.