feat: removes greenkeeper readme template badge
fixes oclif/oclif#70
MODIFY
templates/README.md.ejs
templates/README.md.ejs
[![CircleCI](https://circleci.com/gh/<%= repository %>/tree/master.svg?style=shield)](https://circleci.com/gh/<%= repository %>/tree/master)
[![Appveyor CI](https://ci.appveyor.com/api/projects/status/github/<%= repository %>?branch=master&svg=true)](https://ci.appveyor.com/project/<%= repository %>/branch/master)
[![Codecov](https://codecov.io/gh/<%= repository %>/branch/master/graph/badge.svg)](https://codecov.io/gh/<%= repository %>)
-[![Greenkeeper](https://badges.greenkeeper.io/<%= repository %>.svg)](https://greenkeeper.io/)
[![Known Vulnerabilities](https://snyk.io/test/github/<%- repository %>/badge.svg)](https://snyk.io/test/github/<%- repository %>)
[![Downloads/week](https://img.shields.io/npm/dw/<%= pjson.name %>.svg)](https://npmjs.org/package/<%= pjson.name %>)
[![License](https://img.shields.io/npm/l/<%= pjson.name %>.svg)](https://github.com/<%= repository %>/blob/master/package.json)

feat: removes greenkeeper readme template badge (#81)

fixes oclif/oclif#70