Added Treeware badge and license

Author: JamesMessinger

README.md

@@ -9,6 +9,7 @@ A [rehype](https://github.com/rehypejs/rehype) plugin that adds a table of conte
 
 [![npm](https://img.shields.io/npm/v/@jsdevtools/rehype-toc.svg)](https://www.npmjs.com/package/@jsdevtools/rehype-toc)
 [![License](https://img.shields.io/npm/l/@jsdevtools/rehype-toc.svg)](LICENSE)
+[![Buy us a tree](https://img.shields.io/badge/Treeware-%F0%9F%8C%B3-lightgreen)](https://plant.treeware.earth/JS-DevTools/rehype-toc)
 
 
 
@@ -261,6 +262,8 @@ License
 --------------------------
 Rehype TOC is 100% free and open-source, under the [MIT license](LICENSE). Use it however you want.
 
+This package is [Treeware](http://treeware.earth). If you use it in production, then we ask that you [**buy the world a tree**](https://plant.treeware.earth/JS-DevTools/rehype-toc) to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats.
+
 
 
 Big Thanks To