upgrade velero to v1.2.0

Signed-off-by: haoshuwei <haoshuwei24@gmail.com>

install/01-velero.yaml

@@ -73,8 +73,8 @@ spec:
       serviceAccountName: velero
       containers:
       - name: velero
-        # sync from gcr.io/heptio-images/velero:latest
-        image: registry.cn-hangzhou.aliyuncs.com/acs/velero:latest
+        # sync from velero/velero:v1.2.0
+        image: registry.cn-hangzhou.aliyuncs.com/acs/velero:v1.2.0
         imagePullPolicy: IfNotPresent
         command:
           - /velero