Update target version from Python 3.8 to 3.9.

toshihikoyanase · toshihikoyanase · commit 99e82f01c13c · 2025-10-18T12:42:04.000+09:00
diff --git a/pyproject.toml b/pyproject.toml
@@ -169,7 +169,7 @@ version = {attr = "optuna_integration.version.__version__"}
 
 [tool.black]
 line-length = 99
-target-version = ['py38']
+target-version = ['py39']
 exclude = '''
 /(
     \.eggs
