fix(configuration): correction on proxy config (webpack#3173)

Author: bard

src/content/configuration/dev-server.md

@@ -1062,8 +1062,10 @@ module.exports = {
   //...
   devServer: {
     proxy: {
-      '/api': 'http://localhost:3000',
-      changeOrigin: true
+      '/api': {
+        target: 'http://localhost:3000',
+        changeOrigin: true
+      }
     }
   }
 };