Rename `python-igraph` to `igraph` in setup.py
Created by: PhilipVinc
The python-igraph name is deprecated and breaks conda builds https://pypi.org/project/python-igraph/0.9.8/#description
Created by: PhilipVinc
The python-igraph name is deprecated and breaks conda builds https://pypi.org/project/python-igraph/0.9.8/#description