Add babel plugin

Signed-off-by: Vitor Mattos <vitor@php.rio>

Author: vitormattos

babel.config.js

@@ -2,4 +2,5 @@ module.exports = {
   presets: [
     '@vue/cli-plugin-babel/preset'
   ],
+  plugins: ['@babel/plugin-transform-private-methods'],
 }