Fixed proxy in quasar-serve (quasarframework#6829)

* Fixed proxy in quasar-serve

It seems module exports was changed so previous require doesnt work anymore
source: https://github.com/chimurai/http-proxy-middleware#tldr

* Update quasar-serve

Co-authored-by: Razvan Stoenescu <razvan.stoenescu@gmail.com>

Author: lconnected

cli/bin/quasar-serve

@@ -204,9 +204,9 @@ if (ssrDetected === false) {
     }
     file = require(file)
 
-    const proxy = require('http-proxy-middleware')
+    const { createProxyMiddleware } = require('http-proxy-middleware')
     file.forEach(entry => {
-      app.use(entry.path, proxy(entry.rule))
+      app.use(entry.path, createProxyMiddleware(entry.rule))
     })
   }