transformers safetensors gemma2 text-generation mergekit merge arxiv:2306.01708 base_model:google/gemma-2-2b base_model:merge:google/gemma-2-2b base_model:google/gemma-2-2b-it base_model:merge:google/gemma-2-2b-it autotrain_compatible text-generation-inference endpoints_compatible region:us