chore: bump ruff from 0.15.20 to 0.15.21 in the pip-development group (#240)

Bumps the pip-development group with 1 update: [ruff](https://github.com/astral-sh/ruff).


Updates `ruff` from 0.15.20 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@0.15.20...0.15.21)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pyproject.toml

@@ -18,7 +18,7 @@ dev = [
     "pytest-timeout==2.4.0",
     "pytest-asyncio==1.4.0",
     "pytest-cov==7.1.0",
-    "ruff==0.15.20",
+    "ruff==0.15.21",
     "bandit==1.9.4",
     "pyright==1.1.411",
     "twine==6.2.0",