Update debug to version 4

Author: realityking

package.json

@@ -38,7 +38,7 @@
     "mocha": "^5.2.0"
   },
   "dependencies": {
-    "debug": "^3.1.0",
+    "debug": "^4.0.0",
     "gonzales-pe": "^4.2.3",
     "node-source-walk": "^4.0.0"
   }