Amend RefreshTokenValidity to match Cognito changes. (#1498)
Amend RefreshTokenValidity to match Cognito changes. (#1498)

* Amend RefreshTokenValidity to match Cognito change

AWS have changed the type for this property from double to integer, updating to match.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-cognito-userpoolclient.html#cfn-cognito-userpoolclient-refreshtokenvalidity
ikben/troposphere,ikben/troposphere,cloudtools/troposphere,cloudtools/troposphere