feat: add flag to force update hertz_client.go

[FGYFFFF]

What type of PR is this?

feat

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• This PR title match the format: <type>(optional scope): <description>
• The description of this PR title is user-oriented and clear enough for others to understand.
• Attach the PR updating the user documentation if the current PR requires user awareness at the usage level. User docs repo

(Optional) Translate the PR title into Chinese.

增加 flag 用来强制更新 hertz_client.go

(Optional) More detailed description for this PR(en: English/zh: Chinese).

en: add flag to force update hertz_client.go
zh(optional):
"hertz_client.go" 是 hz client 的桩代码，他的逻辑可能会有一些变动，之前为避免给用户带来干扰，hz client 的行为是如果存在"hertz_client.go"则不会去重新生成这个文件；如果用户想要使用新的 feature(添加在 hertz_client.go里的)，则需要删除掉这个文件重新生成

(Optional) Which issue(s) this PR fixes:

(Optional) The PR that updates user documentation:

[Duslia]

是不是直接盖掉就行了呀？ 不用给用户选择的机会，现在配置项膨胀的太多了