linkParameter missing in CognitoEventUserPoolsCustomMessageRequest

In the [AWS documentation of custom message lambda trigger for Cognito](https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-lambda-custom-message.html#json-2), there is an example json for an incoming event that contains a _linkParameter_ attribute in request node.

It seams like this linkParameter is actually contained in the events payload, as we are able to use it in a lambda written in typescript with event typed as "any". But with this lib, v1.49.0, there is no such field linkParameter inside _CognitoEventUserPoolsCustomMessageRequest_.

Is this a bug, is there a newer version of the lib somewhere or am I missing something? I do see two ways to work around this limitation:
1. Receiving the event as a json.RawMessage and marshal it myself into an own struct.
2. Try to build the link on my own from codeParameter and some addtional values, I would have to pass as env variables to the lambda.

Both not optimal.

Thanks in advance for an answer