Bump external/ELFIO from 4bc17b6 to c5e56b8

Bumps [external/ELFIO](https://github.com/serge1/ELFIO) from `4bc17b6` to `c5e56b8`.
- [Release notes](https://github.com/serge1/ELFIO/releases)
- [Commits](serge1/ELFIO@4bc17b6...c5e56b8)

---
updated-dependencies:
- dependency-name: external/ELFIO
  dependency-type: direct:production
...

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