Provide a simpler way to make it work in new virtualenvs

[gdubicki]

Hi!

The current "quickstart" is not that quick - it requires you to do extra setup for each new virtualenv: install extra packages, provide extra config and to do it in exactly this order.

I have just filed pypa/virtualenv#2250 to make it easier but perhaps you already have a plan for such or a different improvement that you could share?

[pkit]

You can use --extra-index-url in requirements.txt (provided your pip is sufficiently new)
Then the setup is pretty simple:
pip install pip --upgrade && pip install keyrings.google-artifactregistry-auth
After which you can use: pip install -r requirements.txt
No other config is needed.