Remove postinstall script

This action is no longer needed after serenity-js/serenity-js#2591

Author: fapspirit

package-lock.json

@@ -4,7 +4,6 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "postinstall": "serenity-bdd update",
     "clean": "rimraf target",
     "test": "failsafe clean test:execute test:report",
     "test:execute": "wdio wdio.conf.ts",