[common][serializers] Update iteritems to items for dictionaries

beat/web/common/serializers.py

@@ -283,11 +283,11 @@ class MapDot(dict):
         super(MapDot, self).__init__(*args, **kwargs)
         for arg in args:
             if isinstance(arg, dict):
-                for k, v in arg.iteritems():
+                for k, v in arg.items():
                     self[k] = v
 
         if kwargs:
-            for k, v in kwargs.iteritems():
+            for k, v in kwargs.items():
                 self[k] = v
 
     def __getattr__(self, attr):