Fixed travis build.

Florian Lautenschlager · Florian Lautenschlager · commit 1a183081e83c · 2016-12-05T10:43:04.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 language: ruby
 rvm:
-- 2.2
+- 2.3.3
 
 before_script:
  - chmod +x ./script/cibuild # or do this locally and commit
