build(deps-dev): bump ruff in /tests/ocpp-server in the regular group (…

…#1257)

Bumps the regular group in /tests/ocpp-server with 1 update: [ruff](https://github.com/astral-sh/ruff).


Updates `ruff` from 0.8.3 to 0.8.4
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.8.3...0.8.4)

---
updated-dependencies:
- dependency-name: ruff
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: regular
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>