fix(package): update debug to version 4.0.0

Closes #31

Author: greenkeeper[bot]

package.json

@@ -24,7 +24,7 @@
   },
   "dependencies": {
     "async": "2.5.0",
-    "debug": "2.6.8",
+    "debug": "4.0.0",
     "lodash": "4.17.4"
   },
   "devDependencies": {