fix: remove browser from package.json

Author: pionxzh

package.json

@@ -33,9 +33,7 @@
   ],
   "types": "dist/index.d.ts",
   "jsdelivr": "dist/browser.js",
-  "browser": {
-    "vanilla": "dist/browser.js"
-  },
+  "unpkg": "dist/browser.js",
   "main": "dist/index.js",
   "module": "dist/index.mjs",
   "exports": {