chore(package): update sinon to version 4.3.0

Closes #3

Author: greenkeeper[bot]

package.json

@@ -56,7 +56,7 @@
     "nyc": "^10.0.0",
     "proxyquire": "1.8.0",
     "rewire": "^2.5.2",
-    "sinon": "^2.0.0",
+    "sinon": "^4.3.0",
     "standard": "^10.0.0"
   },
   "nyc": {