build(deps): update dependency ruff to v0.15.6

Author: renovate-bot

pyproject.toml

@@ -55,7 +55,7 @@ dev = [
   "pytest-cov==7.0.0",
   "pytest-gitconfig==0.9.0",
   "pytest-xdist==3.8.0",
-  "ruff==0.15.5",
+  "ruff==0.15.6",
   "taplo==0.9.3",
   "types-backports==0.1.3",
   "types-colorama==0.4.15.20250801",