chore(readme): remove Greenkeeper badge

README.md

@@ -3,7 +3,7 @@
 [![npm](https://img.shields.io/npm/v/rollup-plugin-sourcemaps.svg)](https://www.npmjs.com/package/rollup-plugin-sourcemaps)
 [![Build Status](https://img.shields.io/travis/maxdavidson/rollup-plugin-sourcemaps/master.svg)](https://travis-ci.org/maxdavidson/rollup-plugin-sourcemaps)
 [![Coverage Status](https://img.shields.io/coveralls/maxdavidson/rollup-plugin-sourcemaps/master.svg)](https://coveralls.io/github/maxdavidson/rollup-plugin-sourcemaps?branch=master)
-[![Greenkeeper badge](https://badges.greenkeeper.io/maxdavidson/rollup-plugin-sourcemaps.svg)](https://greenkeeper.io/)
+
 
 [Rollup](https://rollupjs.org) plugin for loading files with existing source maps.
 Inspired by [webpack/source-map-loader](https://github.com/webpack/source-map-loader).