Serialize s3 metadata properly
Add support for parsing S3 metadata types

A special case is required to parsed rest-xml, map types
with a location of header.  The only place this is used is for
S3 metadata types.
Merge branch 'release-0.42.0' into develop

* release-0.42.0:
  Bumping version to 0.42.0
  Update dynamodb to the latest JSON model
  Update JSON models to latest version
Merge branch 's3-metadata' into develop

* s3-metadata:
  Add support for parsing S3 metadata types
  Serialize s3 metadata properly
Remove cli_name from .extra files

This logic can live in the argrename CLI customization.

The only one I didn't pull out was the sns one for endpoint,
because that also has a py_name attribute as well.

I think we might be able to move that out, but I'll have to double
check, and if so, it will be in a separate commit/PR.
Merge branch 'no-cli-name' into develop

* no-cli-name:
  Remove cli_name from .extra files
Bump jmespath version to latest released version 0.4.1
Updated SQS model
Bumping version to 0.43.0
Merge branch 'release-0.43.0'

* release-0.43.0:
  Bumping version to 0.43.0
  Updated SQS model
  Bump jmespath version to latest released version 0.4.1
  Remove cli_name from .extra files
  Add support for parsing S3 metadata types
  Serialize s3 metadata properly