set_new_password_challenge() raises NotAuthorizedException for clients with secret

[dmder]

https://github.com/capless/warrant/blob/60b9cc0f7ccd4a9a37dc93b1bf6bdc3705981149/warrant/aws_srp.py#L240
When I call set_new_password_challenge() for the Cognito client, which does have a client_secret, it fails with botocore.errorfactory.NotAuthorizedException: ... Unable to verify secret hash for client <client_id>. This is due to the fact that "SECRET_HASH" attribute is missing in challenge_response dictionary. After adding SECRET_HASH authentication flow succeedes.

[J-Rojas]

I can confirm this.

PR with a fix is here
#93