build: update repository field

Author: pi0

package.json

@@ -2,7 +2,7 @@
   "name": "h3",
   "version": "1.15.3",
   "description": "Minimal H(TTP) framework built for high performance and portability.",
-  "repository": "unjs/h3",
+  "repository": "h3js/h3",
   "license": "MIT",
   "sideEffects": false,
   "exports": {