.travis.yml in gecko-ruby-0.7.1 vs .travis.yml in gecko-ruby-0.8.0

@@ -1,9 +1,8 @@
 language: ruby
 before_install:
  - gem install bundler
 rvm:
-  - 2.3
   - 2.4
   - 2.5
   - 2.6
   - ruby-head