Update README.md

[amrit1004]

Add Event Bubbling Section to README.md

• Introduced a detailed explanation of event bubbling in JavaScript, including its definition and how it works within the DOM.
• Added a practical example demonstrating event bubbling with a parent div and a child button.
• Explained the difference between event bubbling and event capturing, along with methods to stop event propagation.
• Included a section on real-world use cases, specifically event delegation, to highlight performance benefits.
• Provided references and video resources for further reading and understanding of event bubbling and capturing.

This addition aims to enhance the documentation and provide clear insights into event handling in JavaScript.