clientv3: fix init client error

[happlins]

fix clientv3 init client error

close #14323

Signed-off-by: happlins happlins@foxmail.com

Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

[ahrtr]

Two comments:

1. please signoff the commit using command git rebase HEAD~1 --signoff;
2. Please consider to add a couple of unit tests to verify the changes.

[happlins]

I have modified and added unit tests.

[SimFG]

@happlins you need to combine four commits into one

[happlins]

sorry,I have revised it.

[ahrtr]

The minimum version supported should be 3.4, so probably we should update min at client.go#L510.

Please also consider to enhance the unit test to cover more scenarios,such as,

1. All endpoint versions are up to date;
2. All endpoint versions are out of date;
3. Partially endpoint versions are out of date;

[ahrtr]

any update on this?

[happlins]

I'm sorry. I've been too busy recently. I've modified the minimum version and added unit test

[ahrtr]

LGTM

Thank you @happlins

[ahrtr]

Since there is no response from other maintainers and it's a safe change to me, so let me merge this PR.