Update Readme.md

[Atomic71]

Changelog:

• changed the way Vue 3 integration information pointer is visually presented in the file.

Reasoning:

I found it quite confusing to have a header which said FOR VUE 3 because my first thought was that this is for Vue 3, and then I noticed the little paragraph link below, which I think was well-hidden. I think this simple styling change makes it a bit easier on the eyes and the brain.