feat(contents): Multiple video authors

[DanielKrasny]

Pull Request Template

Description

I've extended my previous PR (#82) to the new parser. YT Music videos can also have multiple authors, so I added the authors key. However, I'm unsure about removing author - I kept it there, returning the first item of authors.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

Checklist:

• 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
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have checked my code and corrected any misspellings