build(deps): bump clap_mangen from 0.2.19 to 0.2.20

Bumps [clap_mangen](https://github.com/clap-rs/clap) from 0.2.19 to 0.2.20.
- [Release notes](https://github.com/clap-rs/clap/releases)
- [Changelog](https://github.com/clap-rs/clap/blob/master/CHANGELOG.md)
- [Commits](clap-rs/clap@clap_mangen-v0.2.19...clap_mangen-v0.2.20)

---
updated-dependencies:
- dependency-name: clap_mangen
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.toml

@@ -35,4 +35,4 @@ tokio = { version = "1.36.0", features = ["macros", "rt-multi-thread"] }
 [build-dependencies]
 clap = { version = "4.5.1", features = ["cargo"] }
 clap_complete = "4"
-clap_mangen = "0.2.19"
+clap_mangen = "0.2.20"