Cython 3.0 Breaks Kiva Build

[corranwebster]

We are seeing C++ errors in the Kiva build - incorrect wrapper code is somehow being generated. There look to be multiple different errors, so it may take a little time to unwind.

In the mean time, we may want to update the build requirements to specify earlier Cython.

[drbsg]

This is affecting v5.3.1 as well on platforms which do not have binary wheels available (in particular Windows). I would very much appreciate a back-port of a fix for this.

[corranwebster]

The work-around in the short-term is to specify "cython<3" in the pyproject.toml before building. I'm not sure we have bandwidth to backport fixes in the near-term, but I will happily review PRs.

[itziakos]

fixes by #1070