pypi / test.pypi project ownership

[justinchuby]

@daquexian could you add onnx as a co-owner of the pypi project, so that future maintainers can publish new releases? Thank you!

[andife]

@daquexian thank you for adding onnx to the pypi repo.

maybe also https://test.pypi.org/project/onnxoptimizer/ would be good