Use loopback address in proxy to avoid appveyor issue

Author: rlamana

test/Client.test.js

@@ -13,7 +13,7 @@ function startProxy(port) {
   proxy.use(
     '/',
     httpProxy({
-      target: 'http://0.0.0.0:8080',
+      target: 'http://localhost:8080',
       ws: true,
       changeOrigin: true,
       proxyTimeout: 30000,