message: Update ChangesetError code to a string literal type and add the new buyer_consent_required error
diff: @@ -270,9 +270,9 @@ interface CalculatedPurchase {
  totalOutstandingSet: MoneyBag;
  }
  -/** Represents an error occurred while calculating or applying a changeset.
  +/** Error code while calculating or applying a changeset.
  *
  - * **Possible values for `code`:**
  + * **Possible values :**
  *
  * - `payment_required` - The original payment method couldn't be charged.
  * - `insufficient_inventory` - An item requested to be added is out of stock.
  @@ -280,12 +280,24 @@ interface CalculatedPurchase {
  * - `unsupported_payment_method` - Indicates that the payment method was unsupported. The payment method used to pay for the initial purchase can't be used to pay for changesets.
  * - `invalid_request` - The request is invalid. It shouldn't be re-sent without modifications.
  * - `server_error` - An unexpected error has happened.
  + * - `buyer_consent_required` - Indicates that the buyer's consent was required in order to apply the changeset, but none was provided.
  + */
  +type ChangesetErrorCode =
  + | 'payment_required'
  + | 'insufficient_inventory'
  + | 'changeset_already_applied'
  + | 'unsupported_payment_method'
  + | 'invalid_request'
  + | 'server_error'
  + | 'buyer_consent_required';
  +
  +/** Represents an error occurred while calculating or applying a changeset.
  */
  interface ChangesetError {
  /** An error code corresponding to an error that occurred while calculating or applying a changeset.
  Useful for grouping errors that can be handled similarily.
  */
  - code: string;
  + code: ChangesetErrorCode;
  /**
  * The error description.
  */
  