update readme

[guritfaq]

Summary by CodeRabbit

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• Documentation: Updated README to reflect the project's transition from "AI-based PR reviewer and summarizer" to "CodeRabbit Pro".
• New Feature: Introduced a new section promoting CodeRabbit Pro, with added badges for Discord, license, and last commit information.
• Chore: Removed the section about CodeRabbit Pro from README, as it is now available on coderabbit.ai.

• Notice: Added a note indicating that the old version is now in maintenance mode and recommending users to install the Pro version.

[github-actions[bot]]

CodeRabbit

Walkthrough

This pull request primarily focuses on updating the README file to reflect the transition from "AI-based PR reviewer and summarizer" to "CodeRabbit Pro". It introduces a new section promoting the Pro version, updates project name, and removes outdated content. The installation instructions remain untouched.

Changes

File	Summary
README.md	The project name has been updated to "CodeRabbit Pro". A new section promoting the Pro version is added with relevant badges. Outdated content about CodeRabbit Pro has been removed. Installation instructions are unchanged.

🐇🎉

With each commit, we hop ahead,

From AI-reviewer, a new path we tread.

Now as CodeRabbit Pro, we shine,

In the world of code, we're the prime!

So here's to changes, big and small,

May our code be strong, and bugs fall! 🥕🎈

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