Bug in subscriptions model

[lukeasrodgers]

The model and rest client signatures for updating a subscription don't match: the subscriptions rest client expects a subscription_id but the model does not pass it.

rest client: https://github.com/synapsepay/SynapsePayRest-Ruby/blob/01140eeeab22acf697ff0e7208cac9140bb29984/lib/synapse_pay_rest/api/subscriptions.rb#L73

model: https://github.com/synapsepay/SynapsePayRest-Ruby/blob/01140eeeab22acf697ff0e7208cac9140bb29984/lib/synapse_pay_rest/models/subscription/subscription.rb#L81

possibly the rest api function signature should be def update(subscription_id:, **payload)