BLD: future-compat issue with numpy (numpy 1.7 deprecated C API)

[neutrinoceros]

Bug report

Bug summary

We've had build-time warnings "Using deprecated NumPy API..." for ever, and until recently there was nothing to be done about it, because the C code using deprecating numpy API was generated by Cython and there was no way to prevent that. However it's now possible with Cython 3.0.

It's not clear exactly when Numpy 1.7 deprecated API will be dropped but with numpy 2.0 around the corner, I'd expect it sooner rather than later.

[neutrinoceros]

Here's the relevant NEP: https://numpy.org/neps/nep-0053-c-abi-evolution.html