[FEATURE] Add backwards compatibility integration tests #37
Description
Is your feature request related to a problem?
Coming from opensearch-project/job-scheduler#242 where I was struggling with fixing backwards compatibility tests for job-scheduler against OpenSearch 3.0. There's way too much going on in that project and debugging is hard.
What solution would you like?
Implement a clean, copyable, clear and robust example of bcw testing in this template that cloning projects can use.