.travis.yml in fluent-plugin-numeric-counter-0.2.3 vs .travis.yml in fluent-plugin-numeric-counter-0.3.0

@@ -1,6 +1,9 @@
 language: ruby
+sudo: false
 rvm:
-  - 1.9.3
   - 2.0.0
-  - 2.1
-  - 2.2
+  - 2.1.8
+  - 2.2.4
+  - 2.3.0
+before_install:
+  - gem update bundler
\ No newline at end of file