chore(package): update sinon to version 4.1.5

Author: greenkeeper[bot]

package.json

@@ -81,7 +81,7 @@
     "mocha": "^4.0.0",
     "prebuild": "^7.0.0",
     "proxyquire": "^1.7.10",
-    "sinon": "^4.0.1"
+    "sinon": "^4.1.5"
   },
   "engines": {
     "node": ">=4.0.0"