Merge pull request #17 from zixia/greenkeeper-phantomjs-prebuilt-2.1.12

phantomjs-prebuilt@2.1.12 breaks build ⚠️

package.json

@@ -52,7 +52,7 @@
     "eventemitter2": "^2.1.0",
     "express": "^4.13.4",
     "npmlog": "^4.0.0",
-    "phantomjs-prebuilt": "^2.1.10",
+    "phantomjs-prebuilt": "^2.1.12",
     "ps-tree": "^1.0.1",
     "retry-promise": "^1.0.0",
     "selenium-webdriver": "^3.0.0-beta-1",