support for deploy.update_config

**Is your feature request related to a problem? Please describe.**
[update_config](https://docs.docker.com/reference/compose-file/deploy/#update_config) configures how the service should be updated, and it particularly useful for rolling updates. podman-compose does not have support for it (and neither does docker-compose for that matter, except perhaps swarm. Adding this feature would be a clear reason to switch from docker-compose!)

**Describe the solution you'd like**
Implement this part of the spec.

**Describe alternatives you've considered**
This looks like an interesting alternative project https://github.com/evolutics/kerek Maybe there's something to be learned?