.travis.yml in api_client_base-1.5.0 vs .travis.yml in api_client_base-1.6.0

@@ -1,5 +1,5 @@
 sudo: false
 language: ruby
 rvm:
-  - 2.3.0
-before_install: gem install bundler -v 1.13.1
+  - 2.6.3
+before_install: gem install bundler -v 2.1.4