Package license condition of use – plant a tree

Hadn't seen this take on supporting open source before.

Text of the license: "This package is Treeware. If you use it in production, then we ask that you [buy the world a tree](https://plant.treeware.earth/{user}/{package}) to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats."