chore(package): update sinon to version 5.0.0 (#59)

Author: greenkeeper[bot]

package.json

@@ -68,7 +68,7 @@
     "istanbul": "^1.1.0-alpha.1",
     "mocha": "^5.0.0",
     "semistandard": "^12.0.0",
-    "sinon": "^4.0.0",
+    "sinon": "^5.0.0",
     "sinon-chai": "^3.0.0"
   }
 }