.travis.yml in pinch_hitter-0.5.6 vs .travis.yml in pinch_hitter-0.6.0

@@ -1,8 +1,7 @@
 language: ruby
 rvm:
-  - 1.9.3
-  - 2.0.0
-  - 2.1.5
-  - 2.2.2
+  - 2.1.9
+  - 2.2.5
+  - 2.3.1
 before_install:
   - gem update bundler