DOC: Pin numpydoc=1.8.0

[fangchenli]

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[mroeschke]

Is there a way for us to replace our numpydoc usage so we could use a numpydoc>=1.9.0 instead?

[fangchenli]

Is there a way for us to replace our numpydoc usage so we could use a numpydoc>=1.9.0 instead?

It probably needs to be fixed from the numpydoc side. We could pin it for now to make the CI green.

[datapythonista]

I'm happy to get this merged for now, and check later if we can require the version after the bug is fixed.

[mroeschke]

Thanks @fangchenli, but I just merged #61744 which allow us to get around the error (skipping validation for objects that don't have docstrings which is probably the right thing to do).

Going to close since we don't need to pin numpydoc anymore