chore(deps): update ruff requirement from ==0.15.* to ==0.16.*

Updates the requirements on [ruff](https://github.com/astral-sh/ruff) to permit the latest version.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.15.0...0.16.0)

---
updated-dependencies:
- dependency-name: ruff
  dependency-version: 0.16.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements-testing.txt

@@ -9,7 +9,7 @@ types-PyYAML ~= 6.0
 # that is incompatible with black 25 (last version supporting Python 3.9).
 black == 25.12.*; python_version >= "3.10"
 black == 25.11.*; python_version < "3.10"
-ruff == 0.15.*
+ruff == 0.16.*
 mypy == 2.3.*; python_version >= "3.10"
 mypy == 1.19.*; python_version < "3.10"
 # pydantic: required by the legacy model_v0 (Pydantic) test suite,