Addition of theme toggle switch

[drishtiisharma]

This is a beginner-friendly Hacktoberfest issue, perfect for those looking to make their first open-source contribution!

As the name suggests, I'd like a theme toggle switch to be added here in the top right corner just as I've marked in the picture below.

[jainritikaa]

Hi! 👋 I’d like to work on this issue for Hacktoberfest. Could you please assign it to me?

[kiransatdive]

I would like to work on this issue. Could you please assign it to me?

[Mrigank118]

Hi, I would like to work on this. Could you please assign it to me?

[drishtiisharma]

sure! @kiransatdive @jainritikaa @Mrigank118

[kiransatdive]

thank you