build(deps): update dependency ruff to v0.15.6 (#85)

Co-authored-by: agibot-world[bot] <246073236+agibot-world[bot]@users.noreply.github.com>

Author: agibot-world[bot]

Makefile

@@ -73,7 +73,7 @@ prerequisites:
 	pipx list --short | grep -q "pipenv 2026.0.3" || pipx install --force pipenv==2026.0.3
 	pipx list --short | grep -q "pre-commit 4.5.1" || pipx install --force pre-commit==4.5.1
 	pipx list --short | grep -q "pyproject-fmt 2.11.1" || pipx install --force pyproject-fmt==2.11.1
-	pipx list --short | grep -q "ruff 0.15.2" || pipx install --force ruff==0.15.2
+	pipx list --short | grep -q "ruff 0.15.6" || pipx install --force ruff==0.15.6
 	pipx list --short | grep -q "watchfiles 1.1.1" || pipx install --force watchfiles==1.1.1
 	pipx list --short | grep -q "twine 6.2.0" || pipx install --force twine==6.2.0