Upgrade to Jekyll 3.10.0

[parkr]

No functionality is changed. Since Ruby 3.0 dropped webrick and Ruby 3.4 is going to drop csv, this adds them back as dependencies.

https://jekyllrb.com/news/2024/06/23/jekyll-3-10-0-released/

Fixes #899. Fixes https://github.com/github/pages-gem/issues/887. Fixes https://github.com/github/pages-gem/issues/864. Fixes https://github.com/github/pages-gem/issues/752.

/cc @yoannchaudet

[parkr]

I believe CI may have spotted this, a very outdated gemspec: https://github.com/github/jekyll-commonmark-ghpages/blob/510cdf1291ff6a76eb1341e7d5976bdcede41e47/jekyll-commonmark-ghpages.gemspec#L17

Looks like that could be loosened to v3.9 or greater.

[yoannchaudet]

Checking on the commonmark side.

[yoannchaudet]

We shall be good now with https://github.com/github/pages-gem/pull/919.

Need to prep a release.