chore(package): update sinon to version 2.1.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -64,6 +64,6 @@
     "mocha": "^3.1.2",
     "nyc": "^10.0.0",
     "proxyquire": "^1.7.1",
-    "sinon": "^1.16.1"
+    "sinon": "^2.1.0"
   }
 }