[FEATURE] Run tests against multiple versions of OpenSearch

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Is your feature request related to a problem?

In #356 we are adding an API spec for the next version of OpenSearch. The tests running currently against 2.15 will fail.

What solution would you like?

1. Expand the test matrix to run against a stable and the next version of OpenSearch.
2. Add a feature that lets one mark the minimum version of server required for tests.
3. Only run tests against any specific version of OpenSearch that are compatible.

Use nightly docker images https://hub.docker.com/r/opensearchstaging/opensearch/tags pointing to next version of opensearch. As it is nightly, it might not have all the plugins installed.

What alternatives have you considered?

Always run tests against the next version of OpenSearch.