chore(python): bump ruff from 0.5.0 to 0.6.8 in /py-polars

Bumps [ruff](https://github.com/astral-sh/ruff) from 0.5.0 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@0.5.0...0.6.8)

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

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

py-polars/requirements-lint.txt

@@ -1,3 +1,3 @@
 mypy==1.11.1
-ruff==0.5.0
+ruff==0.6.8
 typos==1.23.5