Update Travis shield

README.md

@@ -1,4 +1,4 @@
-[![Build Status](https://travis-ci.org/librespot-org/librespot.svg?branch=master)](https://travis-ci.org/librespot-org/librespot)
+[![Build Status](https://travis-ci.org/librespot-org/librespot.svg?branch=dev)](https://travis-ci.org/librespot-org/librespot)
 [![Gitter chat](https://badges.gitter.im/librespot-org/librespot.png)](https://gitter.im/librespot-org/spotify-connect-resources)
 [![Crates.io](https://img.shields.io/crates/v/librespot.svg)](https://crates.io/crates/librespot)