fix(package): update commander to version 4.0.0

Closes #141

Author: greenkeeper[bot]

package.json

@@ -12,7 +12,7 @@
     "babel-polyfill": "^6.22.0",
     "babel-preset-latest": "^6.22.0",
     "babel-register": "^6.22.0",
-    "commander": "^2.9.0",
+    "commander": "^4.0.0",
     "eslint": "^4.1.0",
     "eslint-plugin-babel": "^5.1.0",
     "moment": "^2.18.1",