build(deps): bump ruff from 0.11.0 to 0.11.6 in /requirements

Bumps [ruff](https://github.com/astral-sh/ruff) from 0.11.0 to 0.11.6.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.11.0...0.11.6)

---
updated-dependencies:
- dependency-name: ruff
  dependency-version: 0.11.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements/requirements.txt

@@ -5,4 +5,4 @@ cvxpy == 1.5.3
 pytest == 8.3.5 # For unit test
 pytest-xdist == 3.6.1 # For unit test
 mypy == 1.15.0 # For unit test
-ruff == 0.11.0 # For unit test
+ruff == 0.11.6 # For unit test