chore(package): update surge to version 0.20.4

Closes #187

Author: greenkeeper[bot]

package.json

@@ -96,6 +96,6 @@
     "redux-devtools": "^3.4.1",
     "redux-mock-store": "^1.3.0",
     "sinon": "^4.1.3",
-    "surge": "^0.19.0"
+    "surge": "^0.20.4"
   }
 }