⬆️ Bump ruff in /shifter in the python-dependencies group

Bumps the python-dependencies group in /shifter with 1 update: [ruff](https://github.com/astral-sh/ruff).


Updates `ruff` from 0.8.6 to 0.9.0
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.8.6...0.9.0)

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

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

shifter/requirements_dev.txt

@@ -1 +1 @@
-ruff==0.8.6
+ruff==0.9.0