fix: use configResolved hook

Author: mrlubos

.changeset/curvy-chicken-swim.md

@@ -0,0 +1,5 @@
+---
+'@hey-api/rollup-plugin': patch
+---
+
+fix: use configResolved hook

packages/rollup-plugin/src/index.ts

@@ -7,7 +7,8 @@ export function heyApiPlugin(options?: {
   config?: Parameters<typeof createClient>[0];
 }) {
   return {
-    buildStart: async () => {
+    // TODO: rename to vite-plugin if we end up using `configResolved`
+    configResolved: async () => {
       await createClient(options?.config);
     },
     enforce: 'pre',