Add support for assoc items

- Rebase on current master

Author: Yarwin

godot-macros/src/class/godot_dyn.rs

@@ -67,7 +67,7 @@ pub fn attribute_godot_dyn(input_decl: venial::Item) -> ParseResult<TokenStream>
         }
 
         ::godot::sys::plugin_add!(__GODOT_PLUGIN_REGISTRY in #prv; #prv::ClassPlugin::new::<#class_path>(
-            #prv::PluginItem::DynTraitImpl(#prv::DynTraitImpl::new::<#class_path, dyn #trait_path>()))
+            #prv::PluginItem::DynTraitImpl(#prv::DynTraitImpl::new::<#class_path, dyn #trait_path #assoc_type_constraints>()))
         );
 
     };