### Is there an existing issue for this?

- [X] I have searched the existing issues and read the documentation

### Question

I am using serverless framework with localstack and I am unable to define an `AWS::OpenSearchService::Domain` resource. I guess I'll have to use `AWS::Elasticsearch::Domain` instead but it is deprecated. Are there any plans to add `AWS::OpenSearchService::Domain` resource soon? 

### Anything else?

_No response_
call_safe(cluster_1.shutdown)
@pytest.mark.skip_offline
class TestCustomBackendManager:
    def test_custom_backend(self, httpserver, monkeypatch):
        monkeypatch.setattr(config, "OPENSEARCH_ENDPOINT_STRATEGY", "domain")
        monkeypatch.setattr(config, "OPENSEARCH_CUSTOM_BACKEND", httpserver.url_for("/"))
        
        httpserver.expect_request("/").respond_with_json(
            {
                "name": "om",
                "cluster_name": "opensearch",
                "cluster_uuid": "gREewvVZR0mIswR-8-6VRQ",
                "version": {
                    "number": "7.10.0",
                    "build_flavor": "default",
                    "build_type": "tar",
                    "build_hash": "51e9d6f22758d0374a0f3f5c6e8f3a7997850f96",
                    "build_date": "2020-11-09T21:30:33.964949Z",
                    "build_snapshot": False,
                    "lucene_version": "8.7.0",
                    "minimum_wire_compatibility_version": "6.8.0",
                    "minimum_index_compatibility_version": "6.0.0-beta1",
                },
                "tagline": "You Know, for Search",
            }
        )
        httpserver.expect_request("/_cluster/health").respond_with_json(
            {
                "cluster_name": "opensearch",
                "status": "green",