.travis.yml in null-logger-0.1.1 vs .travis.yml in null-logger-0.1.3

@@ -1,7 +1,7 @@
 language: ruby
 rvm:
-  - 2.1.7
   - 2.2.3
   - 2.3.0
+  - 2.3.1
 script:
   - bundle exec rake