@weave.op() doesn't appear to work with **kwargs argument type.

## The problem
Issue wandb/weave#1408 (closed, 6 comments): I get the error `KeyError: 'model'` for the following code snippet: ```python import weave @weave.op() def fn(**kwargs): print(kwargs["model"]) weave.init("scratch-test") fn(model="gpt-4-turbo") ```

## The fix
weave.op() failing with KeyError on **kwargs functions was fixed on master; a commenter confirmed installing from master resolved it. If your @weave.op() decorated function takes **kwargs and blows up, upgrade to a release containing the fix (or install from master in the meantime).

## Notes
Thread: https://github.com/wandb/weave/issues/1408. Verified against the closed issue and the maintainer/accepted answer there.