Update to node 10 in .travis.yml

greenkeeper[bot] · greenkeeper[bot] · commit b4e122e1368e · 2018-04-27T12:02:32.000Z
diff --git a/.travis.yml b/.travis.yml
@@ -5,5 +5,6 @@ node_js:
   - 6
   - 5
   - 4
+  - 10
 after_script:
   - npm run coveralls
