Update train_sequence.py (#487)

Fixed model dump

Co-authored-by: Mohammad Amin Nabian <m.a.nabiyan@gmail.com>

examples/cfd/vortex_shedding_mesh_reduced/train_sequence.py

@@ -277,7 +277,7 @@ def backward(self, loss):
             ),
             "w",
         ) as json_file:
-            json_file.write(C.json(indent=4))
+            json_file.write(C.model_dump_json(indent=4))
 
     # initialize loggers
     initialize_wandb(