Add feature to specify the version of synapse-worker

[Andy-Wu-2022]

What would you like to be added:

Add feature to specify the version of synapse-worker

Why is this needed:

Currently, it is:

    image: ghcr.io/serverlessworkflow/synapse-worker:latest
    imagePullPolicy: IfNotPresent

By default, the version of synapse-worker will NOT update when updating the version of synapse itself. It will possibly cause some inconsistency.

thanks.