Webhook API Updates

Breaking change - Problem Details error response format

After positive feedback from our Webhook API private beta participants, we updated the Webhook API to use the Problem Details standard format for error responses.

For API consumers, the previous JSON array format for expressing errors has been replaced with a JSON object that describes the error in a standard format.

Benefits include:

• Adoption of an industry standard.
• SKY Applications no longer need to handle an array just to pull the one error condition.
• The error types for a given endpoint are included in documentation (OpenAPI) so they can be proactively coded against and accounted for by the SKY application.

User identifier properties

We added new added_by_id and last_changed_by_id properties to some of the event types, including constituent record added, constituent record changed, constituent address added, constituent address changed, gift added, and gift changed events. The properties contain the identifier of the user who added and/or changed the record.