.travis.yml in oxr-0.5.0 vs .travis.yml in oxr-0.6.0

@@ -1,6 +1,5 @@
 language: ruby
 rvm:
-  - 2.2.7
-  - 2.3.4
-  - 2.4.1
-before_install: gem install bundler -v 1.14.6
+  - "2.6"
+  - "2.7"
+  - "3.0"