Cannot load `the_pile_openwebtext2`
Hi! I've merged a PR to use `int32` instead of `int8` for `reddit_scores`, so it should work now.


### Describe the bug

I met the same bug mentioned in #3053 which is never fixed. Because several `reddit_scores` are larger than `int8` even `int16`. https://huggingface.co/datasets/the_pile_openwebtext2/blob/main/the_pile_openwebtext2.py#L62

### Steps to reproduce the bug

```python3
from datasets import load_dataset
dataset = load_dataset("the_pile_openwebtext2")
```

### Expected behavior

load as normal.

### Environment info

- `datasets` version: 2.10.0
- Platform: Linux-5.4.143.bsk.7-amd64-x86_64-with-glibc2.31
- Python version: 3.9.2
- PyArrow version: 11.0.0
- Pandas version: 1.5.3