.travis.yml in autorespawn-0.6.0 vs .travis.yml in autorespawn-0.6.1

@@ -1,8 +1,9 @@
 language: ruby
 rvm:
-  - 2.1.6
-  - 2.2.2
-before_install: gem install bundler -v 1.10.5
+  - 2.1.8
+  - 2.2.5
+  - 2.3.1
+before_install: gem install bundler
 script:
     - bundler exec rake
     - bundler exec rake test