Update transformers to 5.12.1

[pyup-bot]

This PR updates transformers from 5.12.0 to 5.12.1.

Changelog

5.12.1

Updated the lower bound for PEFT and a fix for auto tokenizer to properly resolve the mistral tokenizer (when `mistral-common` is installed). This is similar to v.5.10.3 minus the fixes that were already included in the main release - vLLM will first target 5.10.3 :hugs: 

* Fix `peft` lower bound 46605 by hmellor (46605)
* mistral common backend fix 46667 by itazap (46667)


**Full Changelog**: https://github.com/huggingface/transformers/compare/v5.12.0...v5.12.1

Links

• PyPI: https://pypi.org/project/transformers
• Changelog: https://data.safetycli.com/changelogs/transformers/
• Repo: https://github.com/huggingface/transformers