add 120b and deepspeed zero3 examples (#3035) [skip ci]

* add 120b and deepspeed zero3 examples

* add a bit of flavor and cleanup gpt oss readme

* fix: remove expert vram usage

* fix: remove redundant EOS token from eot_tokens

* feat: add 120B to docs

---------

Co-authored-by: NanoCode012 <nano@axolotl.ai>

examples/gpt-oss/gpt-oss-20b-fft-deepspeed-zero3.yaml

@@ -0,0 +1,58 @@
+base_model: openai/gpt-oss-20b
+use_kernels: false
+model_quantization_config: Mxfp4Config
+model_quantization_config_kwargs:
+  dequantize: true
+
+plugins:
+  - axolotl.integrations.cut_cross_entropy.CutCrossEntropyPlugin
+
+experimental_skip_move_to_device: true  # prevent OOM by NOT putting model to GPU before sharding
+
+datasets:
+  - path: HuggingFaceH4/Multilingual-Thinking
+    type: chat_template
+    field_thinking: thinking
+    template_thinking_key: thinking
+
+dataset_prepared_path: last_run_prepared
+val_set_size: 0
+output_dir: ./outputs/gpt-oss-out/
+
+sequence_len: 4096
+sample_packing: true
+
+wandb_project:
+wandb_entity:
+wandb_watch:
+wandb_name:
+wandb_log_model:
+
+gradient_accumulation_steps: 2
+micro_batch_size: 1
+num_epochs: 1
+
+optimizer: adamw_torch_8bit
+lr_scheduler: constant_with_warmup
+learning_rate: 2e-5
+
+bf16: true
+tf32: true
+
+flash_attention: true
+attn_implementation: kernels-community/vllm-flash-attn3
+
+gradient_checkpointing: true
+activation_offloading: true
+
+logging_steps: 1
+saves_per_epoch: 1
+
+warmup_ratio: 0.03
+
+special_tokens:
+eot_tokens:
+  - "<|end|>"
+
+# choose the zero3 configuration that best fits your system capabilities
+deepspeed: deepspeed_configs/zero3_bf16.json