Add support for AnnData 0.10.0

[martinkim0]

Is your feature request related to a problem? Please describe.
The release candidate for AnnData 0.10.0 is out now - it would be great if the changes could be tested out here since we're looking to add support for it too in scvi-tools.

Describe the solution you'd like
Known bugs:

• mudata._core.io._read_h5mu_mod should not pass in dtype to AnnData.__init__

[gtca]

Hey Martin,

There's #53 that implements this as part of the 0.3 release.
That's the next planned release, which also comes with many other changes. That should be alright especially considering the dtype change will probably not land in 0.10 after all (scverse/anndata#1137).

Does that sound reasonable to you?

[martinkim0]

Ah got it, was not aware of that! Sounds good