Supporting Ruby 2.6.6 and other security releases
Ruby 2.6.6 was a security release, and came out on 3/31/20 (https://www.ruby-lang.org/en/news/2020/03/31/ruby-2-6-6-released/). It's not yet available in setup-ruby so things like CI jobs can't run Ruby 2.6.6 yet and will output: ##[error]Version 2.6.6 not found. It looks like this kind of lag has been raised as an issue for previous Ruby releases (eg, https://github.com/actions/setup-ruby/issues/8) but I don't see anything on the releases this week.
It seems like one alternative is to swap the job to run in a Ruby container instead of on the runner. Another alternative is to use https://github.com/ruby/setup-ruby, which worked for me as a drop-in replacement and includes 2.6.6.
Thanks!
Thanks @kevinrobinson! I have temporarily switched over to ruby/setup-ruby as a result of your post and everything is happy. Thanks for raising this issue for the rest of us. Cheers 🍻