Added cancel + detail endpoints

Added:

• cancel mandates (sync + async)
• retrieve a single status of a mandate (rate-limits apply)

Added idempotency header

Minor release with following changes:

• addition of Idempotency headers
• added function for remove/cancel mandate
• added function for removal of a transaction provided it wasn't sent to the bank yet

Kudos to M0nkor

Release 1.0.0

Major (but breaking changes)

• Refactored the callbacks into more user friendlier generators
• Added model classes to avoid working with dictionaries

Special thanks to Ruben De Smedt

First release to NuGet

v0.1.0

CI/CD publish README