Change upstream to maintained fork
As @rgacogne pointed out, the previous maintainer died and a fork has been created to continue the project. This fork is actively maintained, has had numerous new releases and is what's being packaged at pypi. This pull requests switched upstream to the maintained fork.
The project also started using poetry and pyproject.toml instead of setup.py. I think I converted the build commands appropriately.
Closes #1 (closed)