Merge pull request #8952 from zalando-incubator/container-registry.zalando.net/teapot/etcd-backup

etcd-backup: Update to version master-28

Author: mikkeloscar

cluster/manifests/etcd-backup/cronjob.yaml

@@ -31,7 +31,7 @@ spec:
           restartPolicy: Never
           containers:
           - name: etcd-backup
-            image: container-registry.zalando.net/teapot/etcd-backup:master-27
+            image: container-registry.zalando.net/teapot/etcd-backup:master-28
             env:
             - name: ETCD_S3_BACKUP_BUCKET
               value: "{{ .Cluster.ConfigItems.etcd_s3_backup_bucket }}"