update readme

[harjotgill]

Summary by OpenAI

Release Notes

• New Feature: Added information about gpt-4 and gpt-3.5-turbo OpenAI models, and a note on the cost of using gpt-4.
• Documentation: Clarified instructions for reviewing code changes, emphasizing the use of fenced code blocks for new content and replacement suggestions, and clarified the line number range mapping for replacement suggestions.
• Chore: Updated configuration options for summarizing the diff within 50 words.

"With GPT-4 and GPT-3.5-turbo,
Our PR reviewer's now in the know.
Clearer instructions, better summaries,
This update is sure to please."

[github-actions]

🤖 OpenAI

High-level Summary

The changes in this pull request aim to improve the functionality and usability of the OpenAI ChatGPT-based PR reviewer and summarizer. The updates include adding information about two OpenAI models, gpt-4 and gpt-3.5-turbo, that are used for different tasks, as well as clarifying instructions for reviewing code changes. Additionally, the action.yml file has been updated to include configuration options for summarizing the diff within 50 words.

Files Summary

File	Summary
README.md	Added information about gpt-4 and gpt-3.5-turbo OpenAI models, and a note on the cost of using gpt-4.
action.yml	Updated configuration options for summarizing the diff within 50 words.
src/review.ts	Clarified instructions for reviewing code changes, emphasizing the use of fenced code blocks for new content and replacement suggestions, and clarified the line number range mapping for replacement suggestions.

---

Chat with 🤖 OpenAI Bot (@openai)

• Reply on review comments left by this bot to ask follow-up questions. A review comment is a comment on a diff or a file.
• Invite the bot into a review comment chain by tagging @openai in a reply.

Code suggestions

• The bot may make code suggestions, but please review them carefully before committing since the line number ranges may be misaligned.
• You can edit the comment made by the bot and manually tweak the suggestion if it is slightly off.

---

Files ignored due to filter (1)

Ignored files

• dist/index.js