ssNake uses deprecated NumPy function in1d

When running e.g. a matrix multiply operation on a spectrum.

Deprecated since Numpy 2.0. I don't expect fixing it will break compatibility with our minimums as the new function already existed in Numpy 1.15.

[...]\ssnake\src\hypercomplex.py:280: DeprecationWarning: `in1d` is deprecated. Use `np.isin` instead.
    self.data[(np.in1d(self.hyper, value.hyper), ) + key] = value.data

Listing as blocked until I'm done with the Spectrum.py tests.