Describe environment variable names/expected values in config docs

[ranile]

Checklist

• I am reporting a documentation issue in this repo, not https://docs.ipfs.tech.
• I have searched on the issue tracker for my issue.

Location

https://github.com/ipfs/kubo/blob/master/docs/config.md

Description

Docker docs says I can use environment variables but the names/expected values of those environment variable is defined nowhere.

In this particular case, I would like to set CORS headers but I cannot find out how to do so with just environment variables

[ranile]

Sorry, I misread the docs. Only certain things can be configured with environment variables