fix(hz): fix some problems with hz client code

[Skyenought]

What type of PR is this?

fix

Check the PR title.

• 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.

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

en:

1. Assert all 'api.any' to 'api.post' when generate client code
2. Add addHeaders() method to prevent the generated code from failing to compile

zh(optional):

1. 在hz client 生成文件时, 将 api.any 全部转换为 api.post 注解
2. 增加 addHeaders() 方法，防止生成代码无法通过编译

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

(Optional) The PR that updates user documentation:

cloudwego/cloudwego.github.io#939

[Skyenought]

genClient 不是只有在 client 命令下才执行的嘛😂

[Skyenought]

@FGYFFFF

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (0d25abe) 82.49% compared to head (171b252) 82.54%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1053      +/-   ##
===========================================
+ Coverage    82.49%   82.54%   +0.04%     
===========================================
  Files           98       98              
  Lines        10025    10025              
===========================================
+ Hits          8270     8275       +5     
+ Misses        1258     1254       -4     
+ Partials       497      496       -1     

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[Skyenought]

不好意思, 手快了