feat: Consider forks as valid repositories

[reobin]

Currently, no forks have the opportunity to be featured on vimcolorschemes.com

As discussed in vimcolorschemes/vimcolorschemes#287, forks could be considered as valid repositories as long as they respect certain conditions:

1. Repository name is different than the original repository
2. ... probably more coming once this is worked on

An example of a valid fork is: Iron-E/nvim-highlite

[Iron-E]

Thanks for opening this ticket! Even if it takes a while for the feature to be developed, I'm happy to see it on the roadmap.