use model_dump not dict

Author: sneakers-the-rat

linkml_runtime/dumpers/yaml_dumper.py

@@ -13,7 +13,7 @@ def dumps(self, element: Union[BaseModel, YAMLRoot], **kwargs) -> str:
         # Internal note: remove_empty_items will also convert Decimals to int/float;
         # this is necessary until https://github.com/yaml/pyyaml/pull/372 is merged
 
-        dumper_safe_element = element.dict() if isinstance(element, BaseModel) else element
+        dumper_safe_element = element.model_dump() if isinstance(element, BaseModel) else element
         return yaml.dump(remove_empty_items(dumper_safe_element, hide_protected_keys=True),
                          Dumper=yaml.SafeDumper, sort_keys=False, 
                          allow_unicode=True,