chore(internal): fix ruff target version

Author: stainless-app[bot]

pyproject.toml

@@ -134,7 +134,7 @@ reportPrivateUsage = false
 [tool.ruff]
 line-length = 120
 output-format = "grouped"
-target-version = "py37"
+target-version = "py38"
 
 [tool.ruff.format]
 docstring-code-format = true