Use node6+

.travis.yml

@@ -43,8 +43,8 @@ before_install:
 install:
   - nvm current
   - nvm deactivate
-  - nvm install 4
-  - nvm use 4
+  - nvm install 6
+  - nvm use 6
   - pip install --upgrade pip wheel setuptools tox==1.8.1
 
 before_script:

package.json

@@ -3,8 +3,8 @@
   "version": "0.0.17",
   "private": true,
   "engines": {
-    "node": ">= 4",
-    "npm": ">= 1.1.x"
+    "node": ">= 6.0.0",
+    "npm": ">= 3.0.0"
   },
   "dependencies": {
     "addons-linter": "0.19.1",