Support for AWS::ApiGatewayV2::Api

[mekwall]

Add support for AWS::ApiGatewayV2::Api so that we can deploy WebSockets APIs with aliases as well. Docs can be found here: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-apigatewayv2-api.html

I'm trying to figure out how I can contribute to this myself, but haven't looked at the code yet. My guess is that this should be as simple as using the same implementation that is used to support aliases with deployments using HTTP protocol.

Edit: Looking at the code and the docs it's not as easy as I initially thought.