Updated travis build scripts (from rspec-dev)
requested to merge github/fork/olleolleolle/update-travis-build-scripts-2019-04-18-for-master into master
Created by: olleolleolle
This PR updates the CI matrix to use ruby-2.6.3.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Created by: olleolleolle
This PR updates the CI matrix to use ruby-2.6.3.