Due to the license change of Elasticsearch, we cannot provide you any Docker images for ES 7.11.0 and later.
You can find images for earlier versions at Docker hub:
https://hub.docker.com/r/floragunncom/sg-elasticsearch/tags
Possibly, the SG helm charts are useful for you. Just announced:
https://forum.search-guard.com/t/now-available-as-public-beta-helm-charts-for-search-guard/2132/2