fix: np.nan compatibility for numpy>=2.0.0 🔧

[fkroeber]

Description

Numpy version 2 requires np.nan instead of np.NaN.

Type of change

Select one or more relevant options:

• Bug fix (change which fixes a bug reported in a specific issue)
• New feature (change which adds a feature requested in a specific issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (improved documentation for existing functionality in the package)
• Repository update (change related to non-package files or structures in the GitHub repository)

Checklist:

• I have read and understood the contributor guidelines of this project
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I ran all demo notebooks locally and there where no errors

[augustinh22]

@fkroeber If we make this change, I think we have to change the dependency requirements of semantique to be at least numpy v2, which will require a bit more checking of functionality for potential breaking changes. It seems a few packages (z.B. geopandas) went through a large version change in June last year, so this is likely a larger project to tackle.

https://github.com/numpy/numpy/releases/tag/v2.0.0

This will be useful to go though to make sure nothing else is impacted:

https://numpy.org/doc/stable/numpy_2_0_migration_guide.html