Changes:
- Updated dependencies to ensure support for Python 3.7 environments
- Added support for the uts_mode parameter in HostConfig
- The UpdateConfig constructor now allows rollback as a valid value for failure_action
- Added support for rollback_config in APIClient.create_service, APIClient.update_service, DockerClient.services.create and Service.update
- Credential helpers are now properly leveraged by the build method
- Fixed a bug that caused placement preferences to be ignored when provided to DockerClient.services.create
- Fixed a bug that caused a user value of 0 to be ignored in APIClient.create_container and DockerClient.containers.create