Missing "type" in reasoning summary items

Got this when trying to make a request with reasoning content:

```
Err(invalid_request_error: Missing required parameter: 'input[1].summary[0].type'. (param: input[1].summary[0].type) (code: missing_required_parameter))
```

I think `ReasoningItem.summary` in `async-openai/src/types/responses/response.rs` should be a `Vec<SummaryPart>`, not `Vec<Summary>`; at least that fixed it for me