Update sinon to version 5.0.1 (#41)

Author: greenkeeper[bot]

package.json

@@ -36,7 +36,7 @@
     "eslint": "^4.0.0",
     "eslint-config-lesshint": "^1.0.3",
     "mocha": "^5.0.0",
-    "sinon": "^4.0.0",
+    "sinon": "^5.0.1",
     "vinyl": "^2.1.0"
   },
   "license": "MIT",