Update README.md

Incorrect heading

Author: codeaddslife

README.md

@@ -131,7 +131,7 @@ A collection of awesome browser-side [JavaScript](https://developer.mozilla.org/
 * [Snowpack](https://www.snowpack.dev/) - A lightning-fast frontend build tool, designed for the modern web.
 * [bundle](https://bundle.js.org) - A quick online npm package size checker.
 
-# Minimizers
+## Minimizers
 
 * [Terser](https://github.com/terser/terser) - parser, mangler and compressor toolkit for ES6+
 * [Uglify](https://github.com/mishoo/UglifyJS) - parser / mangler / compressor / beautifier toolkit