feat: Add support for adjustment type and VND currency

[davidgrayston-paddle]

Added

• Support for adjustment type, see related changelog
• Added Vietnamese Dong (VND) as a supported currency for payments related changelog

[davidgrayston-paddle]

items cannot be set to Undefined() by default without moving the argument, which would be a breaking change.

CreateAdjustment.full() and CreateAdjustment.partial() have been introduced to make it easier to create this operation, e.g.

CreateAdjustment.partial(
    Action.Refund,
    [CreateAdjustmentItem("txnitm_01h8bxryv3065dyh6103p3yg28", AdjustmentType.Partial, "100")],
    "error",
    "txn_01h8bxpvx398a7zbawb77y0kp5",
)

CreateAdjustment.full(
    Action.Refund,
    "error",
    "txn_01h8bxpvx398a7zbawb77y0kp5",
)

The constructor can still be used, but items must always be provided, e.g.

CreateAdjustment(
    Action.Refund,
    None,
    "error",
    "txn_01h8bxpvx398a7zbawb77y0kp5",
    AdjustmentActionType.Full,
)

CreateAdjustment(
    Action.Refund,
    Undefined(),
    "error",
    "txn_01h8bxpvx398a7zbawb77y0kp5",
    AdjustmentActionType.Full,
)