fix(package): update debug to version 4.1.1

Closes #34

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "colors": "^1.1.2",
     "cross-env": "^5.1.3",
     "d3-node": "^1.1.3",
-    "debug": "^3.1.0",
+    "debug": "^4.1.1",
     "fast-csv": "^2.4.1",
     "fs-extra": "^6.0.1",
     "microtime": "^2.1.6",