Numpy deprecation warnings

[toaarnio]

The unsized basic datatypes np.float and np.int have been deprecated by Numpy. This is causing warnings at import spectral. Example:

[...] lib/python3.8/site-packages/spectral/config.py:160: DeprecationWarning: `np.int` is a deprecated alias
for the builtin `int`. To silence this warning, 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.

[tboggs]

Thanks for the update!