Remove ruby-head builds from Travis
Remove ruby-head builds from Travis

+update JRuby
We already have ruby-head coverage on Actions.
puma/puma,looker/puma,looker/puma,puma/puma,eileencodes/puma,eileencodes/puma,puma/puma,puma/puma,looker/puma,eileencodes/puma,eileencodes/puma,looker/puma