Move citation.cff validation to pre-commit check

[d33bs]

Description

This PR moves a CITATION.cff validation which currently operates through GitHub Actions workflow tests to a pre-commit check. As a result, I've also moved cffconvert out of the dev dependencies, updated the lockfile, and removed a small mention of the step within the docs.

Closes #160

What is the nature of your change?

• Bug fix (fixes an issue).
• Enhancement (adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).
• This change requires a documentation update.

Checklist

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• I have read the CONTRIBUTING.md guidelines.
• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• New and existing unit tests pass locally with my changes.
• I have added tests that prove my fix is effective or that my feature works.
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[kenibrewer]

LGTM

[d33bs]

Thanks @kenibrewer ! Once the tests for this pass, I plan to merge and release a new patch to help include the functionality from #168 (which may be challenging or block progress for users).