Ruby versions

Ruby version changes are documented at https://ruby-doc.org.

Releases

3.0.0p1	https://www.ruby-lang.org/en/news/2020/09/25/ruby-3-0-0-preview1-released/
2.7.0	https://www.ruby-lang.org/en/news/2019/12/25/ruby-2-7-0-released/
2.6.0	https://www.ruby-lang.org/en/news/2018/12/25/ruby-2-6-0-released/