Mastodawn

updated AWS::Pinpoint::GCMChannel DefaultAuthenticationMethod

Added the DefaultAuthenticationMethod property to specify the default authentication method used for GCM.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-pinpoint-gcmchannel.html #pinpoint #cloudformation

AWS::Pinpoint::GCMChannel - AWS CloudFormation

The GCMChannel resource represents the status and authentication settings of the GCM channel for an application.