chore(deps): update dependency pyupgrade to v3.21.1

Author: renovate[bot]

requirements-dev.txt

@@ -4,7 +4,7 @@ mypy==1.18.2
 perflint==0.8.1
 pre-commit==3.8.0
 pyprojectsort==0.4.0
-pyupgrade==3.21.0
+pyupgrade==3.21.1
 radon[toml]==6.0.1
 removestar==1.5.2
 ruff==0.14.2