remove postinstall hook

Author: viankakrisna

packages/react-dev-utils/package.json

@@ -6,7 +6,6 @@
   "license": "BSD-3-Clause",
   "scripts": {
     "prepublishOnly": "npm run build:prod",
-    "postinstall": "npm run build:prod",
     "build": "cross-env NODE_ENV=development babel src/ -d ./",
     "watch": "cross-env NODE_ENV=development babel -w src/ -d ./",
     "build:prod": "cross-env NODE_ENV=production babel src/ -d ./"