=====
* api-change:``rekognition``: Update rekognition client to latest version
* api-change:``emr``: Update emr client to latest version
* api-change:``xray``: Update xray client to latest version
* feature:Credentials: When creating an assume role profile, you can now specify a credential source outside of the config file using the `credential_source` key.
* api-change:``shield``: Update shield client to latest version
* api-change:``cloudformation``: Update cloudformation client to latest version
* feature:Credentials: When creating an assume role profile, you can now specify another assume role profile as the source. This allows for chaining assume role calls.
* api-change:``codebuild``: Update codebuild client to latest version
* feature:credentials: Adds support for the process credential provider, allowing users to specify a process to call to get credentials.
* api-change:``apigateway``: Update apigateway client to latest version
* api-change:``storagegateway``: Update storagegateway client to latest version
* enhancement:Response: Allow reads of zero on streaming bodies, fixes `1309 <https://github.com/boto/botocore/issues/1309>`__.