refactor: remove unused method (#3542)

Author: alexander-akait

lib/Server.js

@@ -1123,11 +1123,6 @@ class Server {
     return statsObj.toJson(stats);
   }
 
-  use() {
-    // eslint-disable-next-line prefer-spread
-    this.app.use.apply(this.app, arguments);
-  }
-
   setContentHeaders(req, res, next) {
     let { headers } = this.options;
     if (headers) {