Re-enable Limited API

[astrofrog]

This re-enables the limited API now that Cython 3.1.2 is out.

Since last time, we also have Python 3.13 builds on MacOS X and Windows, but @larrybradley feel free to also check locally that everything works fine.

[astrofrog]

I've seen this regions-related failure everywhere, not sure why it's happening now but I think we should basically fix the regions wheels first and release those and that should get rid of the issue here.

[larrybradley]

Why does the win313 test pass on the regions CI though? Is this an intermittent failure? Do you know the cause?

[larrybradley]

It appears to be due to trying to build regions from source (no wheels for 3.13). Photutils has wheels for 3.13.

[astrofrog]

@larrybradley - I'm not quite sure why it suddenly started failing, it looks like somehow GitHub actions might be using a free-threaded version of Python 3.13 on Windows which is very strange. It might be intermittent though. Once the limited API changes are merged for regions we can make a new release which will give us wheels to avoid this issue.