chore: config unpkg

Author: chandq

package.json

@@ -22,6 +22,7 @@
   "main": "lib/cjs/index.js",
   "module": "lib/es/index.js",
   "browser": "lib/umd/index.js",
+  "unpkg": "lib/umd/index.js",
   "types": "lib/index.d.ts",
   "typings": "lib/index.d.ts",
   "exports": {