chore: added packageManager to package.json

package.json

@@ -3,6 +3,7 @@
   "description": "Declarative ThreeJS using Vue Components",
   "version": "2.0.0-beta.9",
   "type": "module",
+  "packageManager": "pnpm@8.2.0",
   "author": "Alvaro Saburido <hola@alvarosaburido.dev> (https://github.com/alvarosabu/)",
   "files": [
     "dist"