Expose rest scorer version to help the deployer expose the endpoint

[Rajimut]

As per the discussion here https://github.com/h2oai/h2oai-serving/pull/914#issuecomment-904287657 it would be nice to know the version of the rest scorer to expose the /contribution endpoint in the deployer. Since this endpoint is only available from version 1.1.0 after this PR #241 - a deployer that consumes rest scorer earlier than this can prevent the endpoint from getting exposed.