Add KTO support (#1640)

* add kto support

* test cleanup

* fix outdated comment

* fix llama3 ultra

* chore: lint

* update to use rl_beta instead of dpo_beta

---------

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

src/axolotl/utils/models.py

@@ -803,7 +803,11 @@ def load_model(
     if not reference_model or cfg.lora_model_dir:
         # if we're not loading the reference model, then we're loading the model for training
         # then the dpo trainer doesn't want the peft model loaded over it, it just wants the lora/peft config
-        if cfg.adapter and cfg.rl in ["dpo", "ipo", "kto_pair"] and not cfg.merge_lora:
+        if (
+            cfg.adapter
+            and cfg.rl in ["dpo", "ipo", "kto_pair", "kto"]
+            and not cfg.merge_lora
+        ):
             _, lora_config = load_lora(model, cfg, inference=False, config_only=True)
         else:
             model, lora_config = load_adapter(model, cfg, cfg.adapter)