Can't install on macos with python3.7

[jocampo2]

The compiled extension is named pyssht.cpython-38-darwin.so after python 3.8 rather than 3.7

[mdavezac]

I can only reproduce this intermitently when installing pyssht on python3.7 as a dependency of a poetry-managed package.
The solution seems to be in the vein of "pip install --force --upgrade numpy pyssht". It might have to do with pip's new dependency resolver.