Fix pydantic deprecation: use model_copy instead of copy

Author: polyaxon-ci

cli/polyaxon/_flow/plugins/__init__.py

@@ -286,7 +286,7 @@ def get_or_create(
         if not config:
             config = cls(auth=auth)
         else:
-            config = config.copy()
+            config = config.model_copy()
         config.set_auth(default=auth)
         config.set_docker()
         config.set_shm()