etcd-backup: Update to version master-29

Update container-registry.zalando.net/teapot/etcd-backup to version master-29

Author: k8s-on-aws-manager-app[bot]

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-28
+            image: container-registry.zalando.net/teapot/etcd-backup:master-29
             env:
             - name: ETCD_S3_BACKUP_BUCKET
               value: "{{ .Cluster.ConfigItems.etcd_s3_backup_bucket }}"