Small change for consistent code style in method

Author: kmvanbrunt

cmd2/cmd2.py

@@ -440,7 +440,7 @@ def __init__(self, completekey: str = 'tab', stdin=None, stdout=None, *,
         self.py_bridge_name = 'app'
 
         # Defines app-specific variables/functions available in Python shells and pyscripts
-        self.py_locals = {}
+        self.py_locals = dict()
 
         # True if running inside a Python script or interactive console, False otherwise
         self._in_py = False