chore(package): update sinon to version 8.0.1

Closes #32

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
     "objection": "^0.8.0",
     "pg": "^7.3.0",
     "pg-escape": "^0.2.0",
-    "sinon": "^4.0.0"
+    "sinon": "^8.0.1"
   },
   "scripts": {
     "test": "node_modules/.bin/mocha --slow 10 --timeout 5000 --reporter spec --recursive tests",