MON-4118: chore: use alertmanager v2 in tests as v1 is not longer supported in Prometheus 3

[machine424]

chore: adjust AdditionalAlertmanagerConfig.[*].APIVersion documentation as v1 is not longer suporter in Prom 3

chore: add a config validation check in case v1 in still using in one of the three AdditionalAlertmanagerConfig (Platform
Prom, UWM Prom and Thanos ruler), this is temp and just meant to guide users during the first 4.X upgrade that ships Prom 3

MON-4118: chore: use alertmanager v2 in tests as v1 is not longer supported in Prometheus 3

---

This will be mentioned in the release notes and maybe we'll upgrade a "known risk/ a warning" for ->4.19 upgrades.

• I added CHANGELOG entry for this change.
• No user facing changes, so no entry in CHANGELOG was needed.

[openshift-ci-robot]

@machine424: This pull request references MON-4118 which is a valid jira issue.

In response to this:

chore: adjust AdditionalAlertmanagerConfig.[*].APIVersion documentation as v1 is not longer suporter in Prom 3

chore: add a config validation check in case v1 in still using in one of the three AdditionalAlertmanagerConfig (Platform
Prom, UWM Prom and Thanos ruler), this is temp and just meant to guide users during the first 4.X upgrade that ships Prom 3

MON-4118: chore: use alertmanager v2 in tests as v1 is not longer supported in Prometheus 3

---

This will be mentioned in the release notes and maybe we'll upgrade a "known risk/ a warning" for ->4.19 upgrades.

• I added CHANGELOG entry for this change.
• No user facing changes, so no entry in CHANGELOG was needed.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: machine424

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[machine424]

/label acknowledge-critical-fixes-only

[juzhao]

/retest-required

[juzhao]

FYI, from https://github.com/prometheus/alertmanager/releases/tag/v0.27.0
v1 API is removed since v0.27.0, PR: prometheus/alertmanager#2970, not 0.28.0 mentioned in error message:
https://github.com/prometheus/alertmanager/pull/2970/files#diff-389f215b8a627266f6eac5be37ea5a33ffe5d39968407f3b2b057f281333c9b1R58
v0.28.0-rc.0 fixes APIv1 deprecation notice, see https://github.com/prometheus/alertmanager/releases/tag/v0.28.0-rc.0, PR: prometheus/alertmanager#3815

[openshift-ci]

@machine424: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/okd-scos-e2e-aws-ovn	bf456b9	link	false	/test okd-scos-e2e-aws-ovn
ci/prow/versions	bf456b9	link	false	/test versions

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[machine424]

FYI, from https://github.com/prometheus/alertmanager/releases/tag/v0.27.0 v1 API is removed since v0.27.0, PR: prometheus/alertmanager#2970, not 0.28.0 mentioned in error message: https://github.com/prometheus/alertmanager/pull/2970/files#diff-389f215b8a627266f6eac5be37ea5a33ffe5d39968407f3b2b057f281333c9b1R58 v0.28.0-rc.0 fixes APIv1 deprecation notice, see https://github.com/prometheus/alertmanager/releases/tag/v0.28.0-rc.0, PR: prometheus/alertmanager#3815

Thanks.
On our side we're only mentioning 0.16.0 where v2 was introduced.

[machine424]

/retest-required