setup.py: Add project_urls for PyPI (#5064)
setup.py: Add project_urls for PyPI (#5064)

Add project_urls dictionary to setup.py with URLs to the Cython documentation, funding, source code and bug tracker. This will add those URLs under the "Project links" section on https://pypi.org/project/cython, making it easy to find these resources directly from PyPI.

cython/cython,cython/cython,cython/cython,cython/cython