fix(package): update debug to version 4.0.0

Author: greenkeeper[bot]

package.json

@@ -12,7 +12,7 @@
     "amqplib": "^0.5.2",
     "apidoc": "^0.17.6",
     "base-64": "^0.1.0",
-    "debug": "^3.1.0",
+    "debug": "^4.0.0",
     "express": "^4.16.2",
     "pg": "^7.4.3",
     "pg-hstore": "^2.3.2",