chore(package): update supertest to version 4.0.0

Closes #27

Author: greenkeeper[bot]

package.json

@@ -53,7 +53,7 @@
     "reparo": "^1.1.1-0",
     "semantic-release": "^4.3.5",
     "sqlite3": "^3.1.8",
-    "supertest": "^2.0.1"
+    "supertest": "^4.0.0"
   },
   "nyc": {
     "exclude": [