Allow setting log_driver when using DockerSwarmOperator

[xjchew]

Description

Allow DockerSwarmOperator to be initialized with a log_driver argument which will be used by Docker SDK to create the service.

Use case/motivation

I have a Docker Swarm with all the nodes set to gelf logging driver as default. However, DockerSwarmOperator requires the services' logging driver to be json-file.
Allowing the logging driver to be specified when initializing the DockerSwarmOperator will allow services to be created with json-file logging driver in order for logs to be retrieved and shown in the UI.

Related issues

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.