awaitOfferings
Fetch the configured offerings for this users. Offerings allows you to configure your in-app products via RevenueCat and greatly simplifies management. See the guide for more info.
Offerings will be fetched and cached on instantiation so that, by the time they are needed, your prices are loaded for your purchase flow. Time is money.
Coroutine friendly version of Purchases.getOfferings.
Return
The Offerings available to this user.
Throws
with a PurchasesError if there's an error retrieving the offerings.