CI: Use ruby 2.4.9, 2.5.7, 2.6.5 (#863)
CI: Use ruby 2.4.9, 2.5.7, 2.6.5 (#863)

* CI: Use ruby 2.4.7, 2.5.6, 2.6.4

* CI: Use 2.4.9, 2.5.7, 2.6.5

drapergem/draper,drapergem/draper,chuck-john/draper,drapergem/draper,chuck-john/draper