Converted to draft only because I do wish to test the wheels on this branch against numpy (2.0b1, 1.26 (most recent stable), and 1.21 (oldest supported by this branch))

There are also some interactions with contourpy, but not in a way that I think it makes sense for us to enforce: if you are using np 2, you need the most recent version of contourpy as well. We do not have a build time dependency on contourpy, so it does not affect wheel building.

I did not pin the version of pybind11 that we need, as that only matters for those building to use with numpy 2. (It is now the most recent stable version)

Everything checked out locally for me (a little hard to test release wheels without images, but managed to get the majority of tests to run and the subset which fail also fail with released mpl 3.8.3 and np 1.26)

Notably, the tests which were known to be problematic with np 2.0b1 and pybind11 2.11 passed on all three test setups (essentially current releases, min version, and prerelease)

We may wish to do the same change to the CIBW job on main (@QuLogic thoughts?) as that will also affect the builds uploaded to nightly.

We can do that as part of the merge up if it's done before branching, I think.