chore(package): update cucumber to version 6.0.4

Closes #232

Author: greenkeeper[bot]

package.json

@@ -88,7 +88,7 @@
     "babel-plugin-transform-class-properties": "^6.24.1",
     "browser-sync": "^2.23.3",
     "chromedriver": "^2.34.1",
-    "cucumber": "^4.0.0",
+    "cucumber": "^6.0.4",
     "cucumber-pretty": "^1.3.2",
     "eslint": "^4.19.1",
     "eslint-config-standard": "^11.0.0",