Build file contains ES6 code

[vonloxx]

When using Gutenberg-JS on Drupal Gutenberg I noticed that some ES6 code is on the build files. This is going to be issue for IE11 support and even Edge on some cases.

[jakub-mroz]

When on Drupal Content type, where Gutenberg is enabled, a Body field is missing you will see "Loading" and it gets stuck.
I hope that helps and it's related.

[flyke]

We use Gutenberg-JS in a custom CMS we built for our clients in laravel + vue.
This exact issue causes the entire CMS to not work on IE11, so for us this is a relative big issue.
Any help is appreciated.