ADD: push checkpoints to mlflow artifact registry (#1295) [skip ci]

* Add checkpoint logging to mlflow artifact registry

* clean up

* Update README.md

Co-authored-by: NanoCode012 <kevinvong@rocketmail.com>

* update pydantic config from rebase

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Co-authored-by: NanoCode012 <kevinvong@rocketmail.com>
Co-authored-by: Wing Lian <wing.lian@gmail.com>

README.md

@@ -763,6 +763,7 @@ wandb_log_model: # "checkpoint" to log model to wandb Artifacts every `save_step
 # mlflow configuration if you're using it
 mlflow_tracking_uri: # URI to mlflow
 mlflow_experiment_name: # Your experiment name
+hf_mlflow_log_artifacts:  # set to true to copy each saved checkpoint on each save to mlflow artifact registry
 
 # Where to save the full-finetuned model to
 output_dir: ./completed-model