feat: Support Structured Outputs

[eiixy]

Support Structured Outputs https://platform.openai.com/docs/guides/structured-outputs/introduction

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.88%. Comparing base (774fc9d) to head (68ee228). Report is 35 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #813 +/- ## ========================================== + Coverage 98.46% 98.88% +0.42% ========================================== Files 24 26 +2 Lines 1364 1347 -17 ========================================== - Hits 1343 1332 -11 + Misses 15 9 -6 Partials 6 6 ```

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[sashabaranov]

Thank you for the PR!

Could we please add some tests here? Both integration and unit tests. I believe we also need to update the ChatCompletionResponse to make this work

[h0rv]

Would love to add this to https://github.com/instructor-ai/instructor-go to streamline parsing the responses into Go structs.

[eiixy]

Thank you for the PR!

Could we please add some tests here? Both integration and unit tests. I believe we also need to update the ChatCompletionResponse to make this work

Thanks for the feedback! I've added the requested unit tests. Please review and let me know if anything else is needed.