fix: fix named expressions in assignment types

Author: pwwang

tests/test_varname.py

@@ -188,9 +188,6 @@ def function():
     assert func == ("func", "func")
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 8), reason="named expressions require Python >= 3.8"
-)
 def test_named_expr():
     from .named_expr import a
 

varname/utils.py

@@ -108,7 +108,7 @@
 ArgSourceType: TypeAlias = Union[ArgSourceType, Tuple[ArgSourceType, ...]]
 ArgSourceType: TypeAlias = Union[ArgSourceType, Mapping[str, ArgSourceType]]
 
-ASSIGN_TYPES = (ast.Assign, ast.AnnAssign)
+ASSIGN_TYPES = (ast.Assign, ast.AnnAssign, ast.NamedExpr)
 AssignType: TypeAlias = Union[ASSIGN_TYPES]  # type: ignore
 
 PY311 = sys.version_info >= (3, 11)