feat(sdk): events

[matoous]

Adds typed event handling with signature verification, callbacks, and resource fetching.

events, err := client.EventsHandler(secret, func(ctx context.Context, event sumup.EventNotification) error {
    log.Printf("Unhandled event: %s %s", event.EventID(), event.EventType())
    return nil
})
if err != nil {
    return err
}

if err := events.OnMemberUpdated(func(ctx context.Context, event *sumup.MemberUpdatedEvent) error {
    member, err := event.FetchObject(ctx)
    if err != nil {
            return err
    }
    log.Printf("Member updated: %s", member.ID)
    return nil
}); err != nil {
    return err
}

if err := events.Handle(ctx, rawBody, signatureHeader); err != nil {
    return err
}

Events (also knows as webhooks) allow integrations to listen for events from SumUp and react to them / update the state on their side.