fix(package): update debug to version 4.0.1

Closes #24

Author: greenkeeper[bot]

package.json

@@ -14,7 +14,7 @@
   "license": "ISC",
   "dependencies": {
     "async": "^2.6.0",
-    "debug": "^3.1.0",
+    "debug": "^4.0.1",
     "lodash": "^4.17.5",
     "request": "^2.83.0",
     "revalidator": "^0.3.1",