[ferret_users] pyferret on M2 macs

[Ryo Furue <furue@xxxxxxxxxx>]

Dear PyFerret users on Mac,

When I tried to install PyFerret on a new mac mini, I needed an extra step, which I document here.

As described here

https://stackoverflow.com/questions/70205633/cannot-install-python-3-7-on-osx-arm64

the conda command looks into this repository

https://conda.anaconda.org/conda-forge/osx-arm64

where PyFerret doesn't exist.

I don't know how conda works at all, but I just blindly tried

## use x86_64 architecture channel(s)
conda config --env --set subdir osx-64

before doing

conda create -n FERRET -c conda-forge pyferret \
    ferret_datasets --yes

Then, pyferret is installed and works normally.

Hope this helps.

Ryo