chore(deps-dev): bump ruff from 0.12.12 to 0.15.5 in /tools/spanner

Bumps [ruff](https://github.com/astral-sh/ruff) from 0.12.12 to 0.15.5.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.12.12...0.15.5)

---
updated-dependencies:
- dependency-name: ruff
  dependency-version: 0.15.5
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]