fix(deps): update module github.com/prometheus/alertmanager to v0.28.1

Signed-off-by: konflux-internal-p02 <170854209+konflux-internal-p02[bot]@users.noreply.github.com>

Author: konflux-internal-p02[bot]

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/go-test/deep v1.0.7
 	github.com/gorilla/handlers v1.5.1
 	github.com/k-sone/snmpgo v3.2.0+incompatible
-	github.com/prometheus/alertmanager v0.22.2
+	github.com/prometheus/alertmanager v0.28.1
 	github.com/prometheus/client_golang v1.11.0
 	github.com/prometheus/common v0.26.0
 	github.com/shirou/gopsutil v2.20.9+incompatible