fix(package): update through2 to version 3.0.1

Closes #23

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "restify-errors": "^5.0.0",
     "sse-stream": "0.0.5",
     "stream-combiner2-withopts": "^2.0.0",
-    "through2": "^2.0.1"
+    "through2": "^3.0.1"
   },
   "devDependencies": {
     "chai": "^3.5.0",