xingxing122
还是检查 prepare upgrade pod 的日志，如果镜像正常更新了，就不可能继续在这一行空指针，
重新执行升级脚本，检查日志，重新核对错误信息
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x2025ccf]
goroutine 1 [running]:
kubesphere.io/ks-upgrade/pkg/jobs/core.(\*upgradeJob).deleteKubeSphereWebhook(0xc000a2f630, {0x2ba2f40, 0x40e7c00})
/workspace/pkg/jobs/core/core.go:429 +0x22f
