Build for Python 3.8
Created by: Zaharid
I have added the external recipes https://github.com/Zaharid/conda-recipes/ to use Github actions and build for python 3.8 and 3.9
and have updated reportengine to be python and os independet and also use github actions
https://github.com/NNPDF/reportengine/
with that we should be able to build for python 3.8. Of course for some reason it only works with new versions of conda build so this #915 (closed) needs to be addressed.
Python 3.9 should be trivial except that you-know-which-package is still missing support for it.