feat: enhance NewsArticleJsonLd and ArticleJsonLd author

[ilyichv]

Description of Change(s):

NewsArticleJsonLd author couldn't be customised with @type and url parameter.
With this PR NewsArticleJsonLd authorName prop accepts also ArticleAuthor.

Also there was no way to override @type property of author. With this PR the default is set to Person but can be customised.

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To help get PR's merged faster, the following is required:

[] Updated the documentation
[x] Unit/Cypress test covering all cases

Please link to relevant Google Docs or schema.org docs for what you are adding so we can review.

• https://schema.org/NewsArticle
• https://schema.org/author

Please have a read of the Contributing Guide for full details.

https://github.com/garmeeh/next-seo/blob/master/CONTRIBUTING.md

[garmeeh]

Hey @ilyichv thank you for the PR. Would you mind updating the documentation for this and I can get this merged and released.

[garmeeh]

No sense in holding this up over a small piece of documentation, so will merge and release.