build(deps): bump clap_mangen from 0.2.14 to 0.2.15

Bumps [clap_mangen](https://github.com/clap-rs/clap) from 0.2.14 to 0.2.15.
- [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-v0.2.14...clap_mangen-v0.2.15)

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

Signed-off-by: dependabot[bot] <[email protected]>