Update sequence_classification.md (#27281)
I'm adding accelerate as one of the libraries to install because otherwise when running the Trainer, the model errorr out with the error.
ImportError: Using the `Trainer` with `PyTorch` requires `accelerate>=0.20.1`: Please run `pip install transformers[torch]` or `pip install accelerate -U`
Further context:
1. I've tried this across different environments so I believe that the environment is not the issue.
2. I had the latest transformers library version running.
3. Typically even after install accelerate and import it, it wouldn't resolve the issue until I restart the notebook and try again.
