v2.2.0

In this release of our open source SDK, we've made a significant update that involves modifying the date types within our returned payloads from string to Instant. Please note that this modification is a breaking change. Here's what has been altered:

• The dates in the models have been transitioned from string to Instant.
• Metrics timestamps are now accurately recorded in Epoch usec.
• In situations where the auth flow token has expired, it will now be automatically refreshed, thereby ensuring a successful request.
• We've added a new state: Refreshing. This state is triggered exclusively when the auth flow token needs a refresh during a customer authorization attempt. Typically, this state acts as a bridge between Authorizing and PollingTransactionStatus states.