update readme

Author: sgoedecke

README.md

@@ -92,7 +92,7 @@ the action:
 | `prompt-file`        | Path to a file containing the prompt. If both `prompt` and `prompt-file` are provided, `prompt-file` takes precedence                             | `""`                                 |
 | `system-prompt`      | The system prompt to send to the model                                                                                                            | `"You are a helpful assistant"`      |
 | `system-prompt-file` | Path to a file containing the system prompt. If both `system-prompt` and `system-prompt-file` are provided, `system-prompt-file` takes precedence | `""`                                 |
-| `model`              | The model to use for inference. Must be available in the [GitHub Models](https://github.com/marketplace?type=models) catalog                      | `gpt-4o`                             |
+| `model`              | The model to use for inference. Must be available in the [GitHub Models](https://github.com/marketplace?type=models) catalog                      | `openai/gpt-4.1`                     |
 | `endpoint`           | The endpoint to use for inference. If you're running this as part of an org, you should probably use the org-specific Models endpoint             | `https://models.github.ai/inference` |
 | `max-tokens`         | The max number of tokens to generate                                                                                                              | 200                                  |