fix: older pythons require resource package

src/black/schema.py

@@ -8,12 +8,13 @@ def get_schema(tool_name: str = "black") -> Any:
     """Get the stored complete schema for black's settings."""
     assert tool_name == "black", "Only black is supported."
 
-    loc = "resources/black.schema.json"
+    pkg = "black.resources"
+    fname = "black.schema.json"
 
     if sys.version_info < (3, 9):
-        with importlib.resources.open_text("black", loc, encoding="utf-8") as f:
+        with importlib.resources.open_text(pkg, fname, encoding="utf-8") as f:
             return json.load(f)
 
-    schema = importlib.resources.files("black").joinpath(loc)  # type: ignore[unreachable]
+    schema = importlib.resources.files(pkg).joinpath(fname)  # type: ignore[unreachable]
     with schema.open(encoding="utf-8") as f:
         return json.load(f)