small change to eliminate obsolete np.int calls

[vjcitn]

Many thanks for contributing to sfaira!

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Description of changes

Please ignore the 'note.fork' file in the PR.

np.int is defunct in recent numpy. We run into

> ui$predict_all() 
Error in eval(ei, envir) : 
  AttributeError: module 'numpy' has no attribute 'int'.
`np.int` was a deprecated alias for the builtin `int`. To avoid this error in 
existing code, use `int` by itself. Doing this will not modify any behavior 
and is safe. When replacing `np.int`, you may wish to use e.g. `np.int64`
or `np.int32` to specify the precision. If you wish to review your current use, 
check the release note link for additional information.
The aliases was originally deprecated in NumPy 1.20; for more details 
and guidance see the original release note at:
    https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations

The changes proposed convert two occurrences of np.int to int and
this permits the function to compute with numpy 1.21.5.

[le-ander]

Thanks a lot!

[vjcitn]

will there be a new release with this repair?

[le-ander]

Sorry for the delay. Everything is now merged into main and a new release was created. This should be available via pypi in the next days. You can already get it now using pip install git+https://github.com/theislab/sfaira.git