fix: auto logic

Author: anshumanv

lib/Server.js

@@ -772,8 +772,10 @@ class Server {
       );
     }
 
+    const shouldFindPort = this.options.port === 'auto';
+    const initialPort = shouldFindPort ? null : port || this.options.port;
     return (
-      findPort(port || this.options.port)
+      findPort(initialPort)
         // eslint-disable-next-line no-shadow
         .then((port) => {
           this.options.port = port;