update deps.

Author: gucong3000

.travis.yml

@@ -2,7 +2,7 @@ sudo: false
 language: node_js
 node_js:
   - node
-  - '4'
+  - "6"
 before_install: npm install --global npm
 script: npm run-script pretest && npm run-script coverage
-after_script: npx istanbul-coveralls
+after_script: nyc report --reporter=text-lcov | npx coveralls