Support for Logstash 8.0.x

[brijos]

Is your feature request related to a problem? Please describe.
As a user who does not want to use Data Prepper, Fluentd, or OpenTelemetry collector, I want the Logstash Output Plugin to support Logstash versions 8.0.x

Describe the solution you'd like

• Add support for Logstash 8.0.x in the Logstash Output Plugin by setting the ecs_compatibility flag to disabled. Below is the sample conf for 8.1 from Prashant:

  output {
  opensearch {
  hosts => ["https://demo-kdyzo22un3dswky6vlb3n6pkcu.us-west-2.es.amazonaws.com:443"]
  index => "cwl"
  action => "create"
  user => "logstash"
  password => "xxxxxx"
  ecs_compatibility => disabled
  ssl => true
  }
  }

• Update the version compatibility matrix to reflect the support - https://opensearch.org/docs/latest/clients/agents-and-ingestion-tools/index/

Describe alternatives you've considered
Unable to use Data Prepper, Fluentd, or OpenTelemetry collector in this case.

Additional context
Add any other context or screenshots about the feature request here.

[brijos]

This work was already done inside https://github.com/awslabs/logstash-output-amazon_es. It should be fairly trivial to complete.