[README] fix title

Author: rexim

README.md

@@ -2,7 +2,7 @@
 
 This library is the next generation of the [NoBuild](https://github.com/tsoding/nobuild) idea.
 
-# Quick Example
+## Quick Example
 
 The only file you need from here is [nob.h](https://raw.githubusercontent.com/tsoding/nob.h/refs/heads/main/nob.h). Just copy-paste it to your project and start using it.