Test with Pydantic V2
Author: lig
Pull request: no

### Feature request

Pydantic V2 is about to be release. There is Pydantic 2.0b3 pre-release version available already https://pypi.org/project/pydantic/2.0b3/

Please, test transformers with Pydantic V2.

There is a special tool that could help with migrating the code base to Pydantic V2 https://github.com/pydantic/bump-pydantic/

### Motivation

Pydantic V2 is known to break things and it deprecates a lot of things, see https://errors.pydantic.dev/v2.0/migration.

Why upgrading? Pydantic is known to be 5-50x faster than Pydantic V1 according to https://docs.pydantic.dev/latest/blog/pydantic-v2-alpha/. This alone looks really beneficial for `transformers`. Apart from that Pydantic V2 brings a lot of new features, see the link above.

### Your contribution

Please, don't hesitate asking for help in [Pydantic Discussions](https://github.com/pydantic/pydantic/discussions) section and/or [report any issues](https://github.com/pydantic/pydantic/issues) encountered in the process.

Comments:
Hi @lig 

Thanks again for the PR #24596. Really appreciated.

Regarding using Pydantic V2, I am afraid that the involved places are not directly in `transformers` codebase.

For example, in 

https://github.com/huggingface/transformers/pull/24596#issuecomment-1615176591

it shows 

```bash
2023-06-30T20:07:31.9883431Z  > [19/19] RUN python3 -c "from deepspeed.launcher.runner import main":
2023-06-30T20:07:31.9883916Z 1.621     from deepspeed.runtime.zero.config import DeepSpeedZeroConfig
2023-06-30T20:07:31.9884613Z 1.621   File "/usr/local/lib/python3.8/dist-packages/deepspeed/runtime/zero/config.py", line 76, in <module>
2023-06-30T20:07:31.9885116Z 1.621     class DeepSpeedZeroConfig(DeepSpeedConfigModel):
2023-06-30T20:07:31.9885814Z 1.621   File "/usr/local/lib/python3.8/dist-packages/pydantic/_internal/_model_construction.py", line 171, in __new__
2023-06-30T20:07:31.9886256Z 1.621     set_model_fields(cls, bases, config_wrapper, types_namespace)
2023-06-30T20:07:31.9886812Z 1.621   File "/usr/local/lib/python3.8/dist-packages/pydantic/_internal/_model_construction.py", line 361, in set_model_fields
2023-06-30T20:07:31.9887329Z 1.621     fields, class_vars = collect_model_fields(cls, bases, config_wrapper, types_namespace, typevars_map=typevars_map)
2023-06-30T20:07:31.9888039Z 1.621   File "/usr/local/lib/python3.8/dist-packages/pydantic/_internal/_fields.py", line 112, in collect_model_fields
2023-06-30T20:07:31.9888950Z 1.621     raise NameError(f'Field "{ann_name}" has conflict with protected namespace "{protected_namespace}"')
2023-06-30T20:07:31.9889546Z 1.621 NameError: Field "model_persistence_threshold" has conflict with protected namespace "
```
which indicates `/usr/local/lib/python3.8/dist-packages/deepspeed/runtime/zero/config.py` using `pydantic`.

It's the 3rd party libraries using pydantic have to do something in order to be run with pydantic V2. Right now, `transformers` can only pin v1 and wait.


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