Bump ruff from 0.15.14 to 0.15.21

Bumps [ruff](https://github.com/astral-sh/ruff) from 0.15.14 to 0.15.21.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.15.14...0.15.21)

---
updated-dependencies:
- dependency-name: ruff
  dependency-version: 0.15.21
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

pyproject.toml

@@ -21,7 +21,7 @@ license = {text = "Apache-2.0"}
 [dependency-groups]
 dev = [
     "cliff>=4.14.0",
-    "ruff>=0.15.14",
+    "ruff>=0.15.21",
     "pre-commit>=4.6.0"
 ]