.travis.yml in seo_cache-0.6.0 vs .travis.yml in seo_cache-0.7.0

@@ -1,5 +1,7 @@
+---
 sudo: false
 language: ruby
+cache: bundler
 rvm:
-  - 2.4.1
-before_install: gem install bundler -v 1.16.1
+  - 2.5.1
+before_install: gem install bundler -v 2.0.1