how to match jruby engine_version to ruby version for rails

Is there a document or easy resource that shows me how to match the Jruby version engine to the Ruby version so I can specify it in my Gemfile for Rails?

Example:

ruby '1.9.3', :engine => 'jruby', :engine_version => '1.7.16'

I'm actually using Ruby 2.6.2 though