chore(package): update sinon to version 9.0.1

Closes #54

Author: greenkeeper[bot]

package.json

@@ -34,7 +34,7 @@
     "mocha": "^6.1.4",
     "nodemon": "^1.19.1",
     "pre-commit": "^1.2.2",
-    "sinon": "^7.3.2",
+    "sinon": "^9.0.1",
     "standard": "^12.0.1",
     "text-encoding": "^0.7.0"
   },