Run eval on CPU instead of GPU

[prasad83]

Use --gpu-device as -1

python eval_human_eval.py \
    --model_name_or_path PyCodeGPT-110M/ \
    --output_dir results/ \
    --num_completions 100 \
    --temperature 0.2 \
    --top_p 0.95 \
    --max_new_tokens 100 \
    --gpu_device -1