jekyll.yml starter workflow broken on updated ubuntu-latest

[evanwill]

The update to ubuntu-latest to 24.04 has broken the default "jekyll.yml" starter workflow. The version of ruby/setup-ruby needs to be updated to work with ubuntu 24.04 image. This is done in an old PR #2538, very simple fix to just update the version--but you might as well get a few more versions more up to date.

Unfortunately this impacts tons of people who have been using the default "jekyll.yml" starter workflow in existing repositories, so there is a lot of broken GitHub Pages jekyll sites right now.

Sorry the issues in this repository are so much spam. Thank you for your help.