Added a new revised IT group BackwardCompatibilityMain. The idea is to catch potential backward compatibility issues that may arise during rolling upgrade.
This test group runs a docker-compose cluster with Overlord & Coordinator service on the previous druid version.
Following env vars are required in the GHA file .github/workflows/unit-and-integration-tests-unified.yml to run this test
DRUID_PREVIOUS_VERSION -> Previous druid version to test backward incompatibility.
DRUID_PREVIOUS_VERSION_DOWNLOAD_URL -> URL to fetch the tar.
Rishabh Singh