Added Build Your Own X on Additional Resources in README.md

[manishp608]

First Contribution

Added Build your own X link

Description

Added link of github

Motivation and Context

Rather than going to codecrafters io going to this additional page seemed better

Types of changes

• Content Update (change which fixes an issue or updates an already existing submission)
• New Article (change which adds functionality)
• [x ] Documentation change

Checklist:

• [x ] My code follows the code style of this project.
• [x ] I have updated the documentation accordingly.
• [ x] I have read the CONTRIBUTING document.
• [ x] I have made checks to ensure URLs and other resources are valid