Feature Request: Support CONDA_CHANNELS to set conda channels

[schlichtanders]

I need to use a local channel to fix some packages, however the need to add it to every single CondaPkt.toml makes the environment less movable to other machines.
It would be much simpler if I could set CONDA_CHANNELS to the list of channels and use that.

I tried to set CONDA_CHANNELS, but it is just ignored and still defaults to conda-forge.

EDIT: I think this is just due to --override-channels flag being set, otherwise the CONDA_CHANNELS would get picked up I guess.

[cjdoris]

I've been wondering about ways to allow the user to modify the channels used (e.g. specifying the priority, or a whitelist or blacklist).

The --override-channels flag is there to ensure only the channels specified in CondaPkg.toml are used. For your case, would it be sufficient to have a setting to disable this flag? Can you try it yourself?