[Bug]: EngineArgs missing value type for lora_dtype

[c3-ali]

Your current environment

Versions of relevant libraries:
[pip3] numpy==1.22.4
[pip3] nvidia-nccl-cu12==2.20.5
[pip3] torch==2.3.0
[pip3] transformers==4.41.1
[pip3] triton==2.3.0
[pip3] vllm-nccl-cu12==2.18.1.0.4.0
[conda] numpy                     1.22.4           py39hc58783e_0    conda-forge
[conda] nvidia-nccl-cu12          2.20.5                   pypi_0    pypi
[conda] torch                     2.3.0                    pypi_0    pypi
[conda] transformers              4.41.1                   pypi_0    pypi
[conda] triton                    2.3.0                    pypi_0    pypi
[conda] vllm-nccl-cu12            2.18.1.0.4.0             pypi_0    pypi
ROCM Version: Could not collect
Neuron SDK Version: N/A
vLLM Version: 0.4.2

🐛 Describe the bug

import vllm
vllm.EngineArgs(model='a', lora_dtype='float16')

raises

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[40], line 1
----> 1 ea = vllm.EngineArgs(model='a', lora_dtype='float16')

TypeError: __init__() got an unexpected keyword argument 'lora_dtype'

Fix

Modify lora_dtype = 'auto' to lora_dtype: str = 'auto' in arg_utils.py.