chore(deps): update quay.io/prometheus/alertmanager docker tag to v0.28.1 (#334)

Co-authored-by: Renovate Bot <[email protected]>

Author: soerenschneider

apps/monitoring/alertmanager/statefulset.yaml

@@ -35,7 +35,7 @@ spec:
           type: RuntimeDefault
       containers:
         - name: alertmanager
-          image: quay.io/prometheus/alertmanager:v0.28.0
+          image: quay.io/prometheus/alertmanager:v0.28.1
           imagePullPolicy: IfNotPresent
           args:
             - --storage.path=/data/