Fix missing target-version in ruff (#474)

My bad, missed in #360

Author: paddyroddy

pyproject.toml

@@ -11,7 +11,7 @@ testpaths = [
 [tool.ruff]
 fix = true
 force-exclude = true
-target-version = "py39"
+target-version = "py311"
 lint.ignore = [
     "COM812", # trailing commas (ruff-format recommended)
     "D203", # no-blank-line-before-class