raise minimum supported numpy version to ≥2.0.0

[orbeckst]

During PR review #5476 (comment) it was mentioned that we should raise the minimum supported NumPy version to ≥2.0.0.

This would allow us to get rid of some legacy constructs (e.g., np.bool_ dtypes) and allow us to address #2988 .

[BradyAJohnston]

Posting support here to reiterate what was said in the issue.

[IAlibay]

Sure, we can do that with the next release - that would match SPEC0.