Update README.md (#201)

Fixed little typo

README.md

@@ -50,7 +50,7 @@ For help on editing plugin code, view the [documentation](https://flutter.io/dev
 | finishTransactionIOS | `String` purchaseToken | `PurchaseResult` | Send finishTransaction call to Apple IAP server. Call this function after receipt validation process |
 | acknowledgePurchaseAndroid | `String` purchaseToken, `String` developerPayload? | `PurchaseResult` | Acknowledge a product (on Android) for `non-consumable` and `subscription` purchase. No-op on iOS. |
 | consumePurchaseAndroid | `String` purchaseToken, `String` developerPayload? | `PurchaseResult` | Consume a product (on Android) for `consumable` purchase. No-op on iOS. |
-| finishTransaction | `String` purchaseToken, `String` deveoperPayloadAndroid?, `bool` isConsumable? } | `PurchaseResult` | Send finishTransaction call that abstracts all `acknowledgePurchaseAndroid`, `finishTransactionIOS`, `consumePurchaseAndroid` methods. |
+| finishTransaction | `String` purchaseToken, `String` developerPayloadAndroid?, `bool` isConsumable? } | `PurchaseResult` | Send finishTransaction call that abstracts all `acknowledgePurchaseAndroid`, `finishTransactionIOS`, `consumePurchaseAndroid` methods. |
 | endConnection | | `String` | End billing connection. |
 | consumeAllItems | | `String` | Manually consume all items in android. Do NOT call if you have any non-consumables (one time purchase items). No-op on iOS. |
 | validateReceiptIos | `Map<String,String>` receiptBody, `bool` isTest | `http.Response` | Validate receipt for ios. |