Huggingface Transformers version should be bumped

[michaelroyzen]

Pinning transformers==4.31.0 is incorrect, as it causes incorrect behavior with Code Llama conversion. The minimum supported transformers version with Code Llama is 4.33.1.

[byshiue]

Thank you for the remind. We will try upgrading the transformers version. It may takes some time to verify the correctness.

[byshiue]

This issue is fixed by this MR #148, you can try on latest main branch. Close this bug. Feel free to reopen if needed.