fix: missing commander dep

Author: shanejonas

package-lock.json

@@ -23,6 +23,7 @@
     "@types/isomorphic-fetch": "0.0.35",
     "ajv": "^6.10.0",
     "colors": "^1.3.3",
+    "commander": "^2.20.0",
     "isomorphic-fetch": "^2.2.1",
     "json-schema-faker": "^0.5.0-rc16",
     "json-schema-ref-parser": "^6.1.0"