use per-file-target-version

Author: Liam-DeVoe

pyproject.toml

@@ -1,9 +1,9 @@
 [tool.ruff]
 line-length = 125
 target-version = "py39"
-# Because we set target-version=py39, ruff can't parse this file at all.
-# I don't think ruff supports per-file target versions.
-extend-exclude = ["test_typealias_py312.py"]
+
+[tool.ruff.per-file-target-version]
+"test_typealias_py312.py" = "py312"
 
 [tool.ruff.lint]
 select = [