NumPy 2.0 Migration

[galenseilis]

NumPy is a dependency of Ciw.

NumPy 2.0 is coming, which is a major version change that purportedly will break some things. I don't know if it will break anything in Ciw yet, but we will want to plan and execute migration.

Some resources:

• https://numpy.org/devdocs/numpy_2_0_migration_guide.html
• https://numpy.org/devdocs/release/2.0.0-notes.html
• https://numpy.org/devdocs/dev/depending_on_numpy.html