Update gitlab-org/build/omnibus-mirror/alertmanager from 0.26.0 to 0.27.0

The following dependencies have been updated by deps:

• gitlab-org/build/omnibus-mirror/alertmanager from 0.26.0 to 0.27.0

---

Release Notes: https://github.com/prometheus/alertmanager/blob/v0.27.0/CHANGELOG.md#0270--2024-02-28

Most notably:

Removal of API v1

The Alertmanager v1 API has been deprecated since January 2019 with the release of Alertmanager v0.16.0. With the release of version 0.27.0 it is now removed. A successful HTTP request to any of the v1 endpoints will log and return a deprecation message while responding with a status code of 410. Please ensure you switch to the v2 equivalent endpoint in your integrations before upgrading.

• Prometheus defaults to the v2 API since Prometheus v2.26

  Note that from this release Prometheus is using Alertmanager v2 by default.

• Omnibus ships v2.49

• API v1 was deprecated in Alertmanager 0.16.0

  At the same time with this release the previous API v1 is being deprecated.