test(travis): Update node versions to test on travis

Author: trodrigues

.travis.yml

@@ -6,8 +6,8 @@ language: node_js
 node_js:
   - "0.10"
   - "3.3"
-  - "4.2"
-  - "5.0"
+  - "4.3"
+  - "5.7"
 script: npm run test:ci
 after_success:
   - curl -Lo travis_after_all.py https://raw.githubusercontent.com/contentful/travis_after_all/master/travis_after_all.py