#### What type of PR is this?
/area ui
/kind cleanup
#### What this PR does / why we need it:
Upgrade Node.js to 22
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/area ui
/kind cleanup
#### What this PR does / why we need it:
Bump pnpm version to 10
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR sets Java 21 as minimal version. After doing that, Halo can only run on Java 21 or newer version.
Fortunately, all plugins and themes won't be affected by the restriction.
> https://docs.gradle.org/current/userguide/toolchains.html#sec:release-flag-toolchain
#### Which issue(s) this PR fixes:
Fixes https://github.com/halo-dev/halo/issues/6867
#### Does this PR introduce a user-facing change?
```release-note
[Action Required] 更新最低运行环境为 Java 21
```
#### What type of PR is this?
/area ui
/kind improvement
/milestone 2.16.x
#### What this PR does / why we need it:
升级 pnpm 的版本至 9，以及 GitHub Actions 的 Node 版本改为了 20。
#### Does this PR introduce a user-facing change?
```release-note
升级 pnpm 的版本至 9
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.13.x
#### What this PR does / why we need it:
This PR supports building Docker image with major version tag, e.g.: `halohub/halo:2`.
#### Which issue(s) this PR fixes:
Fixes https://github.com/halo-dev/halo/issues/4976
#### Does this PR introduce a user-facing change?
```release-note
None
```
