run build on postinstall instead of prepare

Author: nicosefer

package.json

@@ -5,7 +5,7 @@
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "scripts": {
-    "prepare": "npm run build",
+    "postinstall": "npm run build",
     "prepublishOnly": "npm test && npm run lint",
     "preversion": "npm run lint",
     "version": "npm run prettier-format && git add -A src",