Added canMakePayments method to be called in prepare method which was no ops in ios.

Author: hyochan

README.md

@@ -75,6 +75,8 @@ Also there are some other methods that is not supported in ios and implemented i
 Lastly, this module also supports types for typescript users from `0.2.5`.
 
 ## Changelogs
+- **[1.2.3]**
+  + Implemented `canMakePayments` method in ios which is called in `prepare` method in the module. Related [issue](https://github.com/dooboolab/react-native-iap/pull/121).
 - **[1.2.2]**
   + Return an err when it failse to parse json in android related to [issue](https://github.com/dooboolab/react-native-iap/pull/196).
 - **[1.2.0]**
@@ -166,7 +168,7 @@ Lastly, this module also supports types for typescript users from `0.2.5`.
 #### Methods
 | Func  | Param  | Return | Description |
 | :------------ |:---------------:| :---------------:| :-----|
-| prepare |  | `Promise<void>` | Prepare IAP module. Must be called on Android before any other purchase flow methods. No-op on iOS.|
+| prepare |  | `Promise<void>` | Prepare IAP module. Must be called on Android before any other purchase flow methods. In ios, it will simply call `canMakePayments` method and return value.|
 | getProducts | `string[]` Product IDs/skus | `Promise<Product[]>` | Get a list of products (consumable and non-consumable items, but not subscriptions). Note: On iOS versions earlier than 11.2 this method _will_ return subscriptions if they are included in your list of SKUs. This is because we cannot differentiate between IAP products and subscriptions prior to 11.2.  |
 | getSubscriptions | `string[]` Subscription IDs/skus | `Promise<Subscription[]>` | Get a list of subscriptions. Note: On iOS  this method has the same output as `getProducts`. Because iOS does not differentiate between IAP products and subscriptions.  |
 | getPurchaseHistory | | `Promise<Purchase[]>` | Gets an invetory of purchases made by the user regardless of consumption status (where possible) |