JRuby 9.2.16.0 fixes 9.2.15.0's racc issue
JRuby 9.2.16.0 fixes 9.2.15.0's racc issue

Reverts Gemfile changes in a192434909

eileencodes/puma,puma/puma,puma/puma,puma/puma,puma/puma,eileencodes/puma,eileencodes/puma,eileencodes/puma