Remove deprecated Gratipay link.

Author: bardiharborow

README.md

@@ -2,7 +2,6 @@
 
 [![npm](https://img.shields.io/npm/v/babel-plugin-transform-es2015-modules-strip.svg?style=flat-square&maxAge=2592000)](https://www.npmjs.com/package/babel-plugin-transform-es2015-modules-strip)
 [![License](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square)](https://github.com/bardiharborow/babel-plugin-transform-es2015-modules-strip/blob/master/LICENSE)
-[![Gratipay](https://img.shields.io/gratipay/user/BardiHarborow.svg?maxAge=2592000&style=flat-square)](https://gratipay.com/~BardiHarborow/)
 
 > A Babel plugin that strips import and export declarations.