Elasticsearch 9 support

[nsano-rururu]

https://github.com/elastic/elasticsearch/releases/tag/v9.0.0-beta1
https://hub.docker.com/r/elastic/elasticsearch/tags
Once the official version of elasticsearch 9 is released, it will be necessary to check its operation.

[nsano-rururu]

Elasticsearch 7.17.x reaches end of support nine months after 9.0.0 is released

[nsano-rururu]

@jertel
elasticsearch9.0.0、kibana 9.0.0 support
Kibana discover also seems to be fine.

elastalert2 2.23.0～

[jertel]

Ok. If you want to officially add support for that version feel free to submit a PR. Thanks for reviewing that version.

[artemisent]

Hello all, what is the status on Elasticsearch v9.0 support?

[jertel]

This PR has the latest updates: #1666

I'm in no hurry to support a x.0 version, but you're welcome to pick up that PR if you're interested in contributing back to the project.

[nsano-rururu]

@artemisent
Elasticsearch9 works with elastalert2 2.23.0 or later. No problems so far.