Bump github.com/prometheus/alertmanager from 0.26.0 to 0.27.0

Bumps [github.com/prometheus/alertmanager](https://github.com/prometheus/alertmanager) from 0.26.0 to 0.27.0.
- [Release notes](https://github.com/prometheus/alertmanager/releases)
- [Changelog](https://github.com/prometheus/alertmanager/blob/main/CHANGELOG.md)
- [Commits](prometheus/alertmanager@v0.26.0...v0.27.0)

---
updated-dependencies:
- dependency-name: github.com/prometheus/alertmanager
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -2,4 +2,4 @@ module github.com/dadevel/alertmanager-signal-receiver
 
 go 1.14
 
-require github.com/prometheus/alertmanager v0.26.0
+require github.com/prometheus/alertmanager v0.27.0