language: ruby
rvm:
  - 2.4.7
  - 2.6.4
services:
  - memcached
notifications:
  email: false

language: ruby
rvm:
  - 2.4.9
  - 2.5.7
  - 2.6.5
services:
  - memcached
notifications:
  email: false

Use latest Ruby on Travis
Use latest Ruby on Travis

Added 2.5.7 since we test that for our other projects (twingly-amqp,
twingly-url, etc.).
