[in_app_purchase] README should include instructions of calling completePurchase. #51902
Description
After upgrade in_app_purchase package 0.2.0 to 0.3.1, all Non consumable products are refunded after three days.
So I search why purchases are refunded.
And finally I got solution.
In Document of in_app_purchase, We should call completePurchase only iOS after purchased non consumable product.
But 0.3.1+1 completePurchase said,
/// Warning! Failure to call this method and get a successful response within 3 days of the purchase will result a refund on Android.
/// The [consumePurchase] acts as an implicit [completePurchase] on Android.
If you don't call completePurchase on android purchase, All of that are refunded after three day....
Flutter team have to write this warning on README!!!