fixed initial npm file error

stripe_to_invoice/next.config.ts

@@ -1,16 +1,7 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  output: 'standalone',
+  output: "standalone",
-  experimental: {
-    turbo: {
-      rules: {
-        '*.css': {
-          loaders: ['postcss-loader'],
-        },
-      },
-    },
-  },
 };
 
 export default nextConfig;