chore(addons): modify cronjob images pull policy

Author: EamonZhang

addons/mysql-cluster/8.0/chart/mysql-cluster/templates/cluster/cronjob.yaml

@@ -30,7 +30,7 @@ spec:
           initContainers:
             - name: backup-wait
               image: registry.drycc.cc/drycc/python-dev:latest
-              imagePullPolicy: {{.Values.imagePullPolicy}}
+              imagePullPolicy: {{ .Values.image.pullPolicy | quote }}
               args:
               - netcat
               - -v