Update dependencies, consolidate requirements, and tweak coverage

[desilinguist]

• Consolidate the two requirements files into one.
• Update sciklit-learn version in requirements. I pinned scikit-learn as >=1.2.0,<1.3.0 since SKLL usually doesn't break for patch updates to scikit-learn.
• Remove the use of nose-cov and modify the CI configuration files to use coverage directly.
• Simplify .coveragerc file.
• Remove pyproject.toml and add .isort.cfg file since the former interferes with test coverage computation.
• Remove previously identified patch for Lars learner since it's no longer needed with scikit-learn v1.2.0.

Note: the coverage number is a little lower because previously we were accidentally including the examples and tests folders in the coverage results which obviously makes no sense.

[codecov[bot]]

Codecov Report

Base: 96.91% // Head: 95.36% // Decreases project coverage by -1.55% :warning:

Coverage data is based on head (23145b3) compared to base (26ab7ab). Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #721 +/- ## ========================================== - Coverage 96.91% 95.36% -1.55% ========================================== Files 63 28 -35 Lines 9292 3386 -5906 ========================================== - Hits 9005 3229 -5776 + Misses 287 157 -130 ``` | [Impacted Files](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService) | Coverage Δ | | |---|---|---| | [skll/learner/\_\_init\_\_.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-c2tsbC9sZWFybmVyL19faW5pdF9fLnB5) | `97.15% <ø> (-0.02%)` | :arrow_down: | | [tests/other/custom\_metrics2.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvb3RoZXIvY3VzdG9tX21ldHJpY3MyLnB5) | | | | [tests/other/majority\_class\_learner.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvb3RoZXIvbWFqb3JpdHlfY2xhc3NfbGVhcm5lci5weQ==) | | | | [tests/test\_voting\_learners\_expts\_4.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF92b3RpbmdfbGVhcm5lcnNfZXhwdHNfNC5weQ==) | | | | [tests/test\_voting\_learners\_api\_3.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF92b3RpbmdfbGVhcm5lcnNfYXBpXzMucHk=) | | | | [tests/test\_voting\_learners\_expts\_5.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF92b3RpbmdfbGVhcm5lcnNfZXhwdHNfNS5weQ==) | | | | [tests/test\_regression.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF9yZWdyZXNzaW9uLnB5) | | | | [tests/test\_voting\_learners\_api\_1.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF92b3RpbmdfbGVhcm5lcnNfYXBpXzEucHk=) | | | | [tests/test\_voting\_learners\_expts\_1.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF92b3RpbmdfbGVhcm5lcnNfZXhwdHNfMS5weQ==) | | | | [tests/test\_cv.py](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService#diff-dGVzdHMvdGVzdF9jdi5weQ==) | | | | ... and [26 more](https://codecov.io/gh/EducationalTestingService/skll/pull/721?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService) | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=EducationalTestingService)

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