add a cool banner image in the readme

[sudiptob2]

I am looking for a simple banner
some ref:

• canva template. This template might be a ref point, but you have to use relevant props, text, etc. Also color combination must be chosen while keeping leetcode in mind.
• Another repo chkware their banner is also pretty simple but effective

[iamrubayet]

bhai i will do that

[RitwikGanguly]

@sudiptob2 add me in this issue, I can make a banner for the readme, And also I am quite familiar with Canva as well.....

[sudiptob2]

@RitwikGanguly I don't know why but the current image I am using in the readme seems OK enough. Maybe I should abandon the idea of changing banner 😞
Nevertheless, if you want to show your take on it, please don't hesitate to create a PR 🙏