Support HAProxy 2.x

[WilliamDEdwards]

Describe the enhancement:

According to https://www.elastic.co/guide/en/beats/metricbeat/current/metricbeat-module-haproxy.html#_compatibility_22, the HAProxy module supports HAProxy versions 1.6, 1.7 and 1.8.

Running HAProxy 2.6, the following error occurs when Metricbeat tries to index events:

WARN        [elasticsearch]        elasticsearch/client.go:414        Cannot index event publisher.Event{Content:beat.Event{Timestamp:time.Date(2023, time.March, 17, 21, 36, 50, 235561684, time.Local), Meta:null, Fields: [...] (status=400): {"type":"mapper_parsing_exception","reason":"failed to parse field [haproxy.stat.check.agent.last] of type [long] in document with id 'LbZK8YYBniYVjaQFG-SZ'. Preview of field's value: 'via agent : up'","caused_by":{"type":"illegal_argument_exception","reason":"For input string: \"via agent : up\""}}, dropping event!

Describe a specific use case for the enhancement or feature:

All 1.x versions are EOL.

[botelastic[bot]]

This issue doesn't have a Team:<team> label.

[botelastic[bot]]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!

[WilliamDEdwards]

Still relevant.