Enhance pre-commit hooks with flake8 and black

[Ygnas]

What this PR does / why we need it:
This PR implements the flake8 linter and black formatting as a pre-commit hook to ensure code quality and adherence to style guidelines.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Checklist:

• Docs included if any changes are user facing

Not sure if I there is a need to exclude something else in the pre-commit config??. If it should be please let me know

[tenzen-y]

Thanks for doing this.
Basically, lgtm

[tenzen-y]

Suggested change

	extend-ignore = W503, E203
	extend-ignore = W503

Instead of ignoring this error, could you fix those errors?

[Ygnas]

Sure I will, there is a small mistake in my flake8 fix as well, wrong indentation. Will fix that as well

[Ygnas]

Black adds whitespace before : in slices, and flake8 complains about it.

Recomended configs for black:
Compatible configuration files can be found here

This behaviour may raise E203 whitespace before ':' warnings in style guide enforcement tools like Flake8. Since E203 is not PEP 8 compliant, you should tell Flake8 to ignore these warnings. More here.

WDYT?

[tenzen-y]

Oh, that makes sense.
Could you add a comment here on why we must ignore E203?

[tenzen-y]

Thank you!
/lgtm
/approve

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[andreyvelich]

@Ygnas Please can create PR to add the pkg directory as well ?
We have some Python files also: https://github.com/kubeflow/katib/tree/master/pkg/suggestion/v1beta1, https://github.com/kubeflow/katib/tree/master/pkg/earlystopping/v1beta1/medianstop

[tenzen-y]

Good point.

[helenxie-bit]

@Ygnas Thank you for your contribution! I'm trying to update a PR (#2393), and the new pre-commit check is working. However, it looks like there's an issue with the compatibility between the isort and black checks. Specifically, I've run "pre-commit run --all-files" locally, but the isort and black checks keep failing for "katib_client.py". It seems that this is because the pre-commit configuration is using the --profile google argument with isort, which has a different style than black. Could you please take a look into this issue?