Update PyPI homepage for dataone.util

[r-b-g-b]

Currently the PyPi "Homepage" link points to a non-existent GitHub repo https://github.com/DataONEorg/d1_tools

Update to point to https://github.com/DataONEorg/d1_python (I think; that's what the dataone.libclient PyPI "Homepage" links to).