Updated ReadTheDocs badge link

README.md

@@ -13,7 +13,7 @@ You're going to love Zammad!
 
 - Build: [![Build Status](https://travis-ci.org/zammad/zammad.svg?branch=develop)](https://travis-ci.org/zammad/zammad)
 - Code: [![Code Climate](https://codeclimate.com/github/zammad/zammad/badges/gpa.svg)](https://codeclimate.com/github/zammad/zammad) [![Coverage Status](https://coveralls.io/repos/github/zammad/zammad/badge.svg)](https://coveralls.io/github/zammad/zammad)
-- Docs: [![Documentation Status](https://readthedocs.org/projects/zammad/badge/?version=latest)](https://docs.zammad.org)
+- Docs: [![Documentation Status](https://readthedocs.org/projects/zammad/badge/)](https://docs.zammad.org)
 - Issues: [![Percentage of issues still open](http://isitmaintained.com/badge/open/zammad/zammad.svg)](https://github.com/zammad/zammad/issues "Percentage of issues still open") [![Average time to resolve an issue](http://isitmaintained.com/badge/resolution/zammad/zammad.svg)](https://github.com/zammad/zammad/issues?q=is%3Aissue+is%3Aclosed "Average time to resolve an issue")
 - Download DEB/RPM: [![](https://img.shields.io/badge/Branch-develop-lightgrey.svg)](https://packager.io/gh/zammad/zammad#develop) [![](https://img.shields.io/badge/Branch-stable-lightgrey.svg)](https://packager.io/gh/zammad/zammad#stable)
 - Docker multi container image: [![](https://images.microbadger.com/badges/image/zammad/zammad-docker-compose:zammad.svg)](https://microbadger.com/images/zammad/zammad-docker-compose:zammad) [![](https://img.shields.io/badge/version-stable-blue.svg)](https://hub.docker.com/r/zammad/zammad-docker-compose)