message: Remove json-loader
  json-loader is now included in webpack4
diff: "estree-walker": "^0.5.0",
  "expect": "^1.16.0",
  "flow-parser": "^0.57.3",
  - "json-loader": "^0.5.3",
  "karma": "^3.0.0",
  "karma-chrome-launcher": "^0.2.3",
  "karma-cli": "^1.0.1",
  