patch: fix estimator kwargs in signature

[FBruzzesi]

Description

Hotfix to properly cloning kwargs in estimator __init__. This is both a bug fix and a breaking change!

Fixes #692

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the style guidelines (ruff)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (also to the readme.md)
• I have added tests that prove my fix is effective or that my feature works
• I have added tests to check whether the new feature adheres to the sklearn convention
• New and existing unit tests pass locally with my changes

[FBruzzesi]

kwarg name changed in one of the latest versions, unrelated to PR

[FBruzzesi]

@koaning there you go! 😇🙌🏼

[koaning]

LGTM! It always surprises me how small edits can suddenly demand a change in so many files 😅

[FBruzzesi]

It always surprises me how small edits can suddenly demand a change in so many files 😅

Wait until a tiny tiny change to support pyarrow via narwhals will become a rework 🙈

As soon as we make a new Narwhals release I should be able to open the PR, yet I would like to wait for pyarrow shift PR to be merged so that also add_lags should be able to operate with pyarrow tables