.travis.yml in agx-0.2.4 vs .travis.yml in agx-0.2.5

@@ -1,5 +1,5 @@
 sudo: false
 language: ruby
 rvm:
-  - 2.4.1
-before_install: gem install bundler -v 1.12.5
+  - 2.5.1
+before_install: gem install bundler -v 1.16.3