.travis.yml in kazan-0.4.0 vs .travis.yml in kazan-0.5.0

@@ -1,8 +1,8 @@
 sudo: false
 language: ruby
 rvm:
-  - 2.3.1
+  - 2.5.0
 gemfile:
   - Gemfile
 before_install:
   - gem install bundler