Merge branch 'fix-resume-imi' of https://github.com/Unity-Technologies/ml-agents into fix-resume-imi

ml-agents/mlagents/trainers/model_saver/torch_model_saver.py

                             f"Did not expect these keys {unexpected_keys} in checkpoint. Ignoring."
                         )
                 else:
-                    # optimizers are treated separately
+                    # If module is not an nn.Module, try to load as one piece
                     mod.load_state_dict(saved_state_dict[name])
 
             # KeyError is raised if the module was not present in the last run but is being