REL: release v1.9.0 for Python 3.13 compatibility

[lucascolley]

Could we get a new numpydoc release? A contributor has run into an incompatibility with Python 3.13 at scipy/scipy#23139. This was fixed in #596 but hasn't been released yet.

We could pin 3.12 in our environment.yml, but a release here seems like the desired long-term solution!

I'm not sure if numpydoc has a designated release manager but pinging @jarrodmillman per previous releases

[lucascolley]

we've just had another SciPy contributor hit this. @stefanv perhaps you could help towards a release here?

[stefanv]

Yes, sure! Thanks for the ping—will coordinate with Jarrod.

[lucascolley]

thanks @jarrodmillman @stefanv !