[prometheus] Update Helm release alertmanager to 1.28.* (#6296)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

charts/prometheus/Chart.lock

@@ -1,15 +1,15 @@
 dependencies:
 - name: alertmanager
   repository: https://prometheus-community.github.io/helm-charts
-  version: 1.27.1
+  version: 1.28.0
 - name: kube-state-metrics
   repository: https://prometheus-community.github.io/helm-charts
   version: 6.3.0
 - name: prometheus-node-exporter
   repository: https://prometheus-community.github.io/helm-charts
-  version: 4.49.0
+  version: 4.49.1
 - name: prometheus-pushgateway
   repository: https://prometheus-community.github.io/helm-charts
-  version: 3.4.1
-digest: sha256:52b59c614cc56ced5c1bde88368e53c8f8ef6de5f4b632d960b40e813a1ab672
-generated: "2025-10-25T01:51:18.275426972Z"
+  version: 3.4.2
+digest: sha256:24da1e63c0e0ad2654fbd81f265198d352272c0ac8e7d49c6dd57099c77b5540
+generated: "2025-11-04T21:10:04.919840238Z"

charts/prometheus/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: prometheus
 # renovate: github=prometheus/prometheus
 appVersion: v3.7.3
-version: 27.42.2
+version: 27.43.0
 kubeVersion: ">=1.19.0-0"
 description: Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/
@@ -32,7 +32,7 @@ maintainers:
 type: application
 dependencies:
   - name: alertmanager
-    version: "1.27.*"
+    version: "1.28.*"
     repository: https://prometheus-community.github.io/helm-charts
     condition: alertmanager.enabled
   - name: kube-state-metrics