Add PR Summary step

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhancement to the GitHub Action with a PR Summary feature utilizing OpenAI.

📊 Key Changes

• Addition of a workflow trigger for when pull requests are opened, closed, or synchronized.
• Inclusion of a new GitHub Action input for enabling automatic PR summaries.
• Configuration of secrets for OpenAI API and OpenAI Azure endpoints for summarization.
• Update GitHub Actions script to generate a summary for PRs.
• Improved documentation and code comments for clarity.

🎯 Purpose & Impact

• 🚀 Purpose: Integrate the power of OpenAI to automatically generate concise and understandable summaries for pull requests. This helps provide immediate context and understanding of the PR changes.
• 👥 Impact: Streamlines the PR review process, enhances collaboration, and aids non-experts in comprehending changes more quickly. This feature is optional and can be triggered on-demand, allowing for flexible use across different workflows.