add rolldown tests for rollup-plugin

Author: radnan

packages/rollup-plugin/package.json

@@ -23,6 +23,7 @@
     "@rollup/plugin-json": "^6.1.0",
     "@vanilla-extract/css": "workspace:^",
     "esbuild": "~0.25.0",
+    "rolldown": "1.0.0-beta.19",
     "rollup": "^4.20.0",
     "rollup-plugin-esbuild": "^6.1.1"
   },