Updated API from documentation release

Author: ct-sdks[bot]

api-specs/checkout/examples/payments/refundPaymentAction.json

@@ -4,5 +4,6 @@
     "centAmount": 10000,
     "currencyCode": "EUR"
   },
+  "transactionId": "example-transactionId",
   "merchantReference": "example-reference"
-}
+}

api-specs/checkout/types/payment-intents/PaymentIntentRefundAction.raml

@@ -15,6 +15,10 @@ properties:
     description: |
       Amount to be refunded. It must be less than or equal to the [captured](/payments-lifecycle#payment-capture) amount.
     type: Amount
+  transactionId?:
+    type: string
+    description: |
+      The identifier of the capture transaction that is associated with the refund action.
   merchantReference?:
     type: string
     description: |