Incompatible environment

[jmduarte]

With the current environment.yml,

conda env create -f environment.yml

fails with

Pip subprocess error:
  Running command git clone --filter=blob:none --quiet https://github.com/thesps/conifer.git /tmp/pip-req-build-wgx0dt_a
ERROR: Package 'conifer' requires a different Python: 3.7.12 not in '>=3.8'

due to a recent update in conifer: https://github.com/thesps/conifer/commit/108715374d5d9839f8e9ac757e9b5cf6bc827145#diff-60f61ab7a8d1910d86d9fda2261620314edcae5894d5aaa236b821c7256badd7L20-R21

I think the simplest solution is to update our environment.yml to use python 3.8.

cc: @quinnanm @thesps