fix(package): update commander to version 4.1.1

Closes #87

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "chalk": "2.4.2",
     "chrome-launcher": "0.10.7",
     "cli-spinner": "0.2.10",
-    "commander": "2.20.0",
+    "commander": "4.1.1",
     "cookie-parser": "1.4.4",
     "debug": "4.1.1",
     "dotenv": "8.0.0",