New Feature: Automated Rollback

If a deployment failed (due to e.g. a timeout or a task placement error) ecs-deploy now is able to automatically rollback the service to the previous task definition revision.
This can be achieved with the new flag --rollback. By default, a failed deployment is not rolled back. The default behavior will change in a future version.

New Feature: Keep old task definitions

By default, the old task definition gets deregistered in ECS after an successful deployment. This can be prevented by passing the new flag --no-deregister. The old task definition then will stay active within ECS.

Improvement: Print ecs-deploy version

The current version of ecs-deploy can not be printed via ecs --version. This might be useful for debugging.

Improvement: More explicit error handling

ecs-deploy now only handles ECS errors. All other errors are bypassed, which might simplify debugging issues with 3rd-party-dependencies.