feat: added shakeFade animation to animate.css

[Nafisa-tamboli]

This pull request introduces a new shakeFade animation to the animate.css library.

✨ Features:

• Combines subtle shake with a fade-out effect
• Useful for error alerts, popups, and attention-grabbing UI components
• Lightweight and smooth animation

📁 Changes made:

• Added shakeFade keyframes in the animation file
• Registered the animation class for global usage

Let me know if any changes are required. Excited to contribute more! 🚀

[Nafisa-tamboli]

Hey maintainers! 👋
I’ve added a new animation called shakeFade to enhance the animation library. It’s simple yet effective for popups or attention-based UI elements. Hope you find it useful — would love your feedback!

Thanks for this awesome open-source project!