Add support for CloudFront http/2 via CloudFormation template

[bjacobel]

Breaking this out into a separate ticket because it's currently blocked on the fact that CloudFormation doesn't support this parameter.

Once they do, just need to add HttpVersion: 'http2', to the CloudFront resource under DistributionConfig.

Here's the forum Q I was going to post before I used search like a not-newb and found somebody else had already gotten an answer:

Hi all,

I'm trying to get the newly announced [CloudFront HTTP/2 support|https://aws.amazon.com/blogs/aws/new-http2-support-for-cloudfront/] to work with my CloudFormation template, but I'm running into several inconsistencies.

The [CloudFront API reference document|http://docs.aws.amazon.com/AmazonCloudFront/latest/APIReference/DistributionConfigDatatype.html] states the existence of an HttpVersion parameter, and says that the behavior of this parameter is "Default: http2 for new web distributions". However, when creating a CloudFront distribution using CloudFormation, and not specifying the HttpVersion parameter, the created CloudFront distribution supports HTTP/1.0 and HTTP/1.1 only.

The [CloudFront DistributionConfig resource type documentation for CloudFormation|http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-cloudfront-distributionconfig.html] does not mention an HttpVersion parameter. Attempting to set this parameter (HttpVersion, a child of DistributionConfig as described in the API ComplexType documentation) results in the following CloudFormation error when creating the stack:

{code}Encountered unsupported property HttpVersion{code}

So it looks to me like two things are wrong:
1: new CloudFront distributions created with CloudFront do not default to the http2 HttpVersion, as claimed in the documentation
2: CloudFormation templates do not support manually specifying an HttpVersion.

Am I doing something wrong, or if I'm right and this support is missing, any estimate on when it will be added?