[MAINT] Update pinned versions

[chiuhoward]

Put changes on a separate branch.

1. Vendorized neurocombat_sklearn and changed imports to fix OneHotEncoder sparse_output argument (Incompatible with scikit-learn >= 1.2 Warvito/neurocombat_sklearn#3).
2. Modified estimator to replace deprecated base_estimator.

[arokem]

Hey @chiuhoward : this is a great start. I just resolved a small conflict with main and the CI is set in motion.

I suggest that rather than cloning neurocombat_sklearn as a submodule (I still don't understand how those work...), we should copy that code (together with it's tests and license) into a module of our repository and fix it here. That way, we can keep maintaining that code into the future here (and maybe eventually upstream it to nilearn?)

[arokem]

Also: I see that the CI is failing because of linting errors. Make sure to install the pre-commit hooks of this repository into your development environment, by running the following in that env and in the top level folder of this repo:

pip install pre-commit 
pre-commit install

That way, every time you make a commit, the linter (ruff) will run on the repo and either fix linting issues or tell you how to fix these issues.

[chiuhoward]

@arokem I think I need more help at this point - something about numpy objects and estimators not having a fit method. Also I've started to rename stuff in the tests too, but I'm not sure if that's good practice either - I could just be breaking good tests so that they pass on my bad code?

[arokem]

Hi @chiuhoward : I think that it would be good to take a divide and conquer approach here, focusing on one test at a time. I would focus first on making the tests that came in together with the neurocombat_sklearn code pass. Once you know that you've updated that code to support newer versions of sklearn, you can move on to update our code to match that.

[arokem]

One more small thing: I would remove the neurocombat_sklearn folder that you have at the top level and move the tests for neurocombat_sklearn to be together with all the other tests.

Actually: instead of explaining, I'll make a PR with that change against your branch. Stand by.

[arokem]

OK - when you merge this PR: chiuhoward#2, that should get into this branch (and you'll need to pull after you do that, so you get that updated locally as well).