Bump ruff from 0.6.6 to 0.6.8

Bumps [ruff](https://github.com/astral-sh/ruff) from 0.6.6 to 0.6.8.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.6.6...0.6.8)

---
updated-dependencies:
- dependency-name: ruff
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

tests/requirements.txt

@@ -1,4 +1,4 @@
-ruff==0.6.6
+ruff==0.6.8
 pytest==8.3.3
 ipdb==0.13.13
 mypy==1.11.2