#### What type of PR is this?
/kind cleanup
#### What this PR does / why we need it:
This PR bumps version to 2.20.9-SNAPSHOT.
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.20.x
#### What this PR does / why we need it:
修正 OpenAPI 的分组匹配规则 之前有很多 PublicAPIs 没有出现在对应的组
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/area core
/kind cleanup
/milestone 2.20.x
#### What this PR does / why we need it:
重新生成 OpenAPI 定义和 API Client，在 https://github.com/halo-dev/halo/pull/6488 中忘了重新生成。
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind cleanup
/area core
#### What this PR does / why we need it:
This PR bumps all version to 2.20.0 to prepare for next development.
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind cleanup
/area core
#### What this PR does / why we need it:
This is a regular updates after a new release.
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind cleanup
/area core
#### What this PR does / why we need it:
Regenerate API docs and client to prevent unrelated changes from other PRs.
#### Does this PR introduce a user-facing change?
```release-note
None
```
John Niang