fix knip test

Author: phonzammi

packages/tests/src/common.ts

@@ -176,6 +176,11 @@ export async function createKnipConfig(projectDir: string, flags: string[], scri
     ignore.push("cdk.out/**");
   }
 
+  if (flags.includes("panda-css")) {
+    entry.push("panda.config.ts");
+    ignoreDependencies.push("postcss");
+  }
+
   const scriptsValues = Array.from(Object.values(scripts));
 
   if (scriptsValues.some((s) => s.includes("tsx "))) {