Feature/docs for using this in a corporate environment

[jamesfricker]

Corporate folks often won't have access to GitHub.com, but some kind of internal mirror of GitHub.

Think makes these features not usable. See others with this issue: https://www.github.com/prefix-dev/pixi/issues/474

There should be a way to supply an alternative GitHub, perhaps as an environment variable or some other means.

[nichmor]

hey @jamesfricker ! Thanks for raising this issue.

I think it is a very good point - maybe we can allow to specify what is the mirror for github compressed mapping in pixi, so others can use their own self-hosted mapping.