Support for np.random.Generator

[stoprightthere]

This is a feature request to support numpy's Generator in addition to (legacy) np.random.RandomState.

[wesselb]

Hey @stoprightthere! Thanks for the feature request. This would be a super good addition. I'm not sure if I have time to work on this on the short term, but I've noted it down on the list of TODOs. :)