Updated git clone in README to pull from stable branch

[Josh-XT]

Background

With changes to master branch, changing git clone to stable branch in the README seems ideal.

Changes

Added -b stable to the git clone in README.

Documentation

Updating it with this PR.

Test Plan

Works on my machine TM.

PR Quality Checklist

• [x] My pull request is atomic and focuses on a single change.
• [x] I have thoroughly tested my changes with multiple different prompts.
• [x] I have considered potential risks and mitigations for my changes.
• [x] I have documented my changes clearly and comprehensively.
• [x] I have not snuck in any "extra" small tweaks changes

[github-actions[bot]]

This pull request has conflicts with the base branch, please resolve those so we can evaluate the pull request.

[p-i-]

This is a mass message from the AutoGPT core team. Our apologies for the ongoing delay in processing PRs. This is because we are re-architecting the AutoGPT core!

For more details (and for infor on joining our Discord), please refer to: https://github.com/Significant-Gravitas/Auto-GPT/wiki/Architecting

[anonhostpi]

@nponeccop what's wrong with specifying the cloned branch?

[Pwuts]

These instructions are no longer in the README, and have been fixed in the docs. Thanks for the submission!