(Ana)conda: Use Miniforge

According to Acaconda's licensing terms we're not allowed to use both Anaconda (the “Anaconda Distribution”) and the Anaconda repositories.

We are allowed, however, to use Miniconda when disable the Anaconda repositories/channels. We haven't been able to do so in a current version of Miniconda.

Instead you can use Miniforge, a drop-in replacement for Miniconda which is preconfigured to use the condaforge repositories/channels.

You can download the conda-forge installer and install it locally yourself: https://conda-forge.org/download/

If you have an old version of Miniconda, run these commands after to have the conda-forge channels (or replace the Miniconda installation with a Miniforge one):

conda config --remove channels defaults
conda config --add channels conda-forge
conda config --set channel_priority strict

(don't mind any error messages from the first command)