fix: resolve @antfu/utils types in dts output (#607)

Author: daopk

tsdown.config.ts

@@ -3,4 +3,7 @@ import { defineConfig } from 'tsdown'
 export default defineConfig({
   entry: ['src/*.ts'],
   format: ['esm', 'cjs'],
+  dts: {
+    resolve: ['@antfu/utils'],
+  },
 })