Postpone dtype deprecation

[gtca]

Please describe your wishes and possible alternatives to achieve the desired result.

As v0.8 has been recommending to use dtype in the constructor (FutureWarning: X.dtype being converted to np.float32 from int64. In the next version of anndata (0.9) conversion will not be automatic. Pass dtype explicitly to avoid this warning. Pass AnnData(X, dtype=X.dtype, ...) to get the future behavour.), it might make the process a bit more gentle if the breaking changes associated with constructor arguments deprecation (#1126) can be postponed to a later release.

[ivirshup]

I would be up for this. I think having at least 2 feature releases/ or a year between deprecating a breaking change and making it is reasonable. It's only been 6 months since 0.9.

I will leave this open for a little more feedback, but am leaning towards postponing at the moment.