Release theme as a gem

[DirtyF]

Hi Mark,

Jekyll supporst gem-based themes, do you plan to release poole as a gem?
I can do some tests and submit a PR if you want.

[DirtyF]

@mdo added you as an owner on the following gems. Let me know if I should just yank all those. Thanks.

https://rubygems.org/gems/jekyll-theme-poole
https://rubygems.org/gems/jekyll-theme-lanyon
https://rubygems.org/gems/jekyll-theme-hyde

[bsmulders]

Thanks for creating the gem @DirtyF

Would it be possible to update it to the latest version of Poole (current master branch) and make the dependency list compatible with Jekyll 4.2.0?

[coreycarvalho]

Any opposition to adding a Github workflow that publishes the gem on new tags? I'd like to get involved in automating this so that I can use it as a gem.

[coreycarvalho]

@mdo @DirtyF I opened a PR to automatically publish gems on new tag pushes #218. Lemme know what you think.