Bug: In some released go-zero version, RPC service discovery failed in a k8s environment

[weizhengde]

Describe the bug
Rpc service discovery is succussful in go-zero version 1.8.3, 1.9.3, but failed in version 1.9.0, 1.10.1. I didn't try all go-zero versions, but the varying behaviors across different versions are confusing, and there is no documentation explaining exactly how to perform service discovery for RPC services in a k8s environment.

To Reproduce
Steps to reproduce the behavior, if applicable:

1. The code is

   import (
        "github.com/zeromicro/go-zero/zrpc"
    )
   
   c := zrpc.RpcClientConf{
        NonBlock: true,
        Target: "k8s://dev/demo-rpc:8080",
   }

   dev is k8s namespace, demo-rpc is service name, 8080 is service port.

2. The error is

   rpc dial: k8s://dev/demo-rpc:8080, error: failed to exit idle mode: failed to start resolver:  endpointslices.discovery.k8s.io is forbidden: User "system:serviceaccount:dev:endpoints-reader" cannot list resource "endpointslices" in API group "discovery.k8s.io" in the namespace "dev", make sure rpc service "k8s://dev/demo-rpc:8080" is already started
   

Expected behavior

1. In all subsequent versions, this configuration syntax is supported.
2. Improve the documentation to clearly explain how to perform RPC service discovery in a k8s environment.

Environments (please complete the following information):

• OS: Linux
• go-zero version 1.10.1
• goctl version 1.10.1