Add Node@^6.0.0 to Travis targets

Author: wooorm

.travis.yml

@@ -1,11 +1,10 @@
 language: node_js
 node_js:
-- '0.10'
 - '0.11'
 - '0.12'
 - '4.0'
 - '5.0'
-- iojs
+- '6.0'
 sudo: false
 after_success:
 - bash <(curl -s https://codecov.io/bash)
@@ -16,6 +15,7 @@ deploy:
       secure: Tvys9puncttZicY3RDRQdfaiqjA50S4kXN0VO5y61GZnXA9jqqkII7z76OeJxzPq0Bp8UUHMOA+Lf8iGMowkLUuexE/a1tzLUMVIctskqMC1dJPEeKn1A1LOH3tkCJCe0Xs6bLF/XtJ0Sd/kVJjkGAAPS/erjYHZNNXv+ksQT1Y=
     on:
       tags: true
+      node: '6.0'
   - provider: releases
     api_key:
       secure: wwCPWGftSTLvwgxgGZCg39K9otbNDHj8slxffh/MTJT/pWYKnBqufQfe6WcCs06c5z6kTddKS7E/ao7jwVlB5/8pIlMzR9cSnCMpJtmh8mFJPSMEMuM4dOVuntNCS58iei7O3PZHuJmQxZY5r6Zrk2egAcsgsDzV6959rxrS3WI=
@@ -24,3 +24,4 @@ deploy:
       - "mdast-util-heading-range.min.js"
     on:
       tags: true
+      node: '6.0'