fix: empty middleware would hang

packages/core/src/latus.js

@@ -109,6 +109,7 @@ export default class Latus {
   invokeMiddleware(hook, ...args) {
     debug('invokeMiddleware(...): %s', hook);
     if (!this.hooks[hook]) {
+      args.pop()();
       return Promise.resolve();
     }
     const parts = hook.split('/');