Change appveyor badge to master branch (#1197)

README.md

@@ -6,7 +6,7 @@
 
 [![Backers on Open Collective](https://opencollective.com/parcel/backers/badge.svg)](#backers) [![Sponsors on Open Collective](https://opencollective.com/parcel/sponsors/badge.svg)](#sponsors)
 [![Travis CI Build Status](https://travis-ci.org/parcel-bundler/parcel.svg?branch=master)](https://travis-ci.org/parcel-bundler/parcel)
-[![Appveyor Build status](https://ci.appveyor.com/api/projects/status/nr7d6qjxj3wwsw6n?svg=true)](https://ci.appveyor.com/project/devongovett/parcel)
+[![Appveyor Build status](https://ci.appveyor.com/api/projects/status/nr7d6qjxj3wwsw6n/branch/master?svg=true)](https://ci.appveyor.com/project/devongovett/parcel)
 [![Coverage](https://img.shields.io/codecov/c/github/parcel-bundler/parcel/master.svg)](https://codecov.io/github/parcel-bundler/parcel/)
 [![David Dependancy Status](https://david-dm.org/parcel-bundler/parcel.svg)](https://david-dm.org/parcel-bundler/parcel)
 [![npm package](https://img.shields.io/npm/v/parcel-bundler.svg)](https://www.npmjs.com/package/parcel-bundler)