chore(package): update sinon to version 2.0.0

https://greenkeeper.io/

Author: greenkeeper[bot]

package.json

@@ -68,7 +68,7 @@
     "husky": "^0.13.0",
     "nyc": "^10.0.0",
     "rimraf": "^2.5.4",
-    "sinon": "^1.17.6",
+    "sinon": "^2.0.0",
     "validate-commit-msg": "^2.10.1"
   },
   "ava": {