Log Message:
py-boto3: updated to 1.5.3

1.5.3
api-change:route53: [botocore] Update route53 client to latest version
api-change:apigateway: [botocore] Update apigateway client to latest version
api-change:mediastore-data: [botocore] Update mediastore-data client to latest \ 
version

1.5.2
bugfix:presigned-url: [botocore] Fixes a bug where content-type would be set on \ 
presigned requests for query services.
api-change:cloudwatch: [botocore] Update cloudwatch client to latest version