docs: Fix README badges

[rerelurelu]

Overview

• Remove Vercel Server badge
• Add Vercel Serverless badge
• Add Vercel Edge budge

What is it?

• [ ] Feature / enhancement
• [ ] Bug
• [x] Docs / tests / types / typos

Description

As mentioned Overview.

Checklist:

• [x] My code follows the developer guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have made corresponding changes to the documentation
• [x] Added new tests to cover the fix / functionality