Bump h3 from 1.15.1 to 1.15.5 in /other/sign-protocol-example

Bumps [h3](https://github.com/h3js/h3) from 1.15.1 to 1.15.5.
- [Release notes](https://github.com/h3js/h3/releases)
- [Changelog](https://github.com/h3js/h3/blob/v1.15.5/CHANGELOG.md)
- [Commits](h3js/h3@v1.15.1...v1.15.5)

---
updated-dependencies:
- dependency-name: h3
  dependency-version: 1.15.5
  dependency-type: indirect
...

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

Author: dependabot[bot]