feat: adding theme-color meta data

[andyford]

adds support for the theme-color meta tag making it available as theme_color at the top level of the response object.

Side note: I noticed that the test in /test/basic/tests.ts labeled should detect title, description and keywords appears to be there twice. I wasn't sure if there was any reason for this though. Should the duplicate be removed? And should the label of the remaining de-duped test read more like should detect favicon, author, description, keywords, title, and theme_color (just to be more accurate)?

[jacktuck]

Thanks

[github-actions[bot]]

:tada: This PR is included in version 6.2.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket:

[andyford]

Thanks

thank YOU! 👍