remove postinstall scripts

Author: Mahad-10

package.json

@@ -15,8 +15,6 @@
   },
   "scripts": {
     "prepare": "npm run build",
-    "postinstall": "npm run postinstall:build",
-    "postinstall:build": "if [ ! -f ts-built/index.js ]; then npm run build; fi",
     "build": "rollup -c",
     "test": "node --experimental-vm-modules node_modules/.bin/jest",
     "lint": "eslint . --ext .ts",