Update to Mangopay API v2.01 - breaking release

This new version of the SDK allows for the use of v2.01 of the Mangopay API, which predominantly is related to the address fields becoming an object instead of a string as they were previously - this is therefore a breaking change and you must update your application (creation/management of Bank Accounts and Users) before being able to use this version of the SDK. More information about the changes required: https://docs.mangopay.com/api-v2-01-overview/