upgrade travis node

diff --git a/.travis.yml b/.travis.yml
index e780b32b66b3c26b84f4c1aa7f5b9a01edb60e85..d2c1fdb863419da08203b8ac642676ed5cef6a72 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ notifications:
   - yiminghe@gmail.com
 
 node_js:
-- 4.0.0
+- 6
 
 before_install:
 - |