add save_only_model option (axolotl-ai-cloud#1634)

Author: jquesnelle

src/axolotl/core/trainer_builder.py

@@ -1123,6 +1123,8 @@ def build(self, total_num_steps):
             # default to saving each epoch if not defined
             training_arguments_kwargs["save_strategy"] = "epoch"
 
+        training_arguments_kwargs["save_only_model"] = self.cfg.save_only_model
+
         if self.cfg.do_bench_eval:
             training_arguments_kwargs["do_bench_eval"] = self.cfg.do_bench_eval
             if self.cfg.bench_dataset:

src/axolotl/utils/config/models/input/v0_4_1/__init__.py

@@ -574,6 +574,7 @@ class Config:
     logging_steps: Optional[int] = None
     early_stopping_patience: Optional[int] = None
     load_best_model_at_end: Optional[bool] = False
+    save_only_model: Optional[bool] = False
 
     neftune_noise_alpha: Optional[float] = None