Deps: Bump pontos from 23.8.5 to 23.9.0 in /helm-version-upgrade

Bumps [pontos](https://github.com/greenbone/pontos) from 23.8.5 to 23.9.0.
- [Release notes](https://github.com/greenbone/pontos/releases)
- [Commits](greenbone/pontos@v23.8.5...v23.9.0)

---
updated-dependencies:
- dependency-name: pontos
  dependency-type: indirect
  update-type: version-update:semver-minor
...

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