Make yarn dev for backends respect the PLUGIN_PORT env var

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/cli/templates/default-backend-plugin/src/service/standaloneServer.ts.hbs

@@ -34,9 +34,12 @@ export async function startStandaloneServer(
     logger,
   });
 
-  const service = createServiceBuilder(module)
-    .enableCors({ origin: 'http://localhost:3000' })
+  let service = createServiceBuilder(module)
+    .setPort(options.port)
     .addRouter('/{{id}}', router);
+  if (options.enableCors) {
+    service = service.enableCors({ origin: 'http://localhost:3000' });
+  }
 
   return await service.start().catch(err => {
     logger.error(err);