regeneratorRuntime Error

Hello,

I've added the `bold-subscriptions-js` to a Shopify site via the CDN method. When ever I access the `BoldSubscriptions.cart.standard.addToCart()` method, I see an error log like this one:

```
Uncaught ReferenceError: regeneratorRuntime is not defined
```

I suspect this is a babel issue based on a cursory search but I'd be happy for it to be user error and something that could be corrected pretty quickly :wink: I can provide more details if needed.

Start by reproducing the CDN integration and calling BoldSubscriptions.cart.standard.addToCart(), then inspect the published JavaScript bundle and its Babel runtime dependencies. Done means the CDN build executes this method without the regeneratorRuntime ReferenceError, with a regression check for this usage.

Written by the indexing model from the issue text.