add withdrawals to the API Swagger specification

We represent them as a list and not a key:value map with stake address as key because clients typically don't know the stake address associated with their wallet, so it'd be quite impractical for them to access this data if returned as a map...

specifications/api/swagger.yaml

@@ -215,6 +215,11 @@ x-amount: &amount
       enum:
         - lovelace
 
+x-stakeAddress: &stakeAddress
+  type: string
+  format: bech32
+  example: stake_addr1sjck9mdmfyhzvjhydcjllgj9vjvl522w0573ncustrrr2rg7h9azg4cyqd36yyd48t5ut72hgld0fg2x
+
 x-addressId: &addressId
   type: string
   format: base58|bech32
@@ -460,6 +465,20 @@ x-transactionOutputs: &transactionOutputs
       address: *addressId
       amount: *transactionAmount
 
+x-transactionWithdrawals: &transactionWithdrawals
+  description: A list of withdrawals from stake addresses.
+  type: array
+  minItems: 0
+  items:
+    type: object
+    additionalProperties: false
+    required:
+      - stake_address
+      - amount
+    properties:
+      stake_address: *stakeAddress
+      amount: *amount
+
 x-transactionResolvedInputs: &transactionResolvedInputs
   description: A list of transaction inputs
   type: array
@@ -902,6 +921,7 @@ components:
         - direction
         - inputs
         - outputs
+        - withdrawals
         - status
       properties:
         id: *transactionId
@@ -912,6 +932,7 @@ components:
         direction: *transactionDirection
         inputs: *transactionInputs
         outputs: *transactionOutputs
+        withdrawals: *transactionWithdrawals
         status: *transactionStatus
 
     ApiWalletDelegationNext: &ApiWalletDelegationNext