[task] Pull Request Summarization from Diffs

### 🚀 The Task

Given the commit diffs for a pull request, the model should be able to summarize the changes made by the source contributor.

### Example

```
Summarize a pull request for the following diffs:

diff --git a/file.py b/file.py
index ...
--- a/file.py
+++ b/file.py
- print("hello world!")
+ print("HELLO WORLD!")
```

### Additional Notes

Reference: [What The Diff](https://whatthediff.ai/)