Ruby 2.1.2 is released!

Ruby 2.1.2 is released. this version includes readline-6.3 build fixes.

https://www.ruby-lang.org/en/news/2014/05/09/ruby-2-1-2-is-released/

ref. https://github.com/sstephenson/ruby-build/issues/550 https://github.com/sstephenson/ruby-build/issues/528 https://github.com/sstephenson/ruby-build/issues/526