feat(typescript-angular): prepare build

Prepare build is required in order to publish

Author: evanjmg

modules/openapi-generator/src/main/resources/typescript-angular/package.mustache

@@ -13,6 +13,7 @@
   ],
   "license": "Unlicense",
   "scripts": {
+    "prepare": "npm run build",
     "build": "ng-packagr -p ng-package.json"
   },
   "peerDependencies": {