Add how to install python deps from git

[zmoog]

Motivation

I know, it's a pretty trivial one, but I never written it down, do IMO it's never too late to add an entry in your personal knowledge management tool.

Change description

Add a simple example of how to install a Python package from a git repo.

Reviewer checklist

• PR address a single concern.
• PR title and description are appropriately filled.
• Changes will be merged in main.
• Changes are covered by tests.
• Logging is meaningful in case of troubleshooting.
• History is clean, commit messages are meaningful (see CONTRIBUTING.md) and are well-formatted.