undid domain change for Ditto website

Signed-off-by: Thomas Jaeckle <thomas.jaeckle@bosch.io>

README.md

@@ -8,7 +8,7 @@
 [![Join the chat at https://gitter.im/eclipse/ditto](https://badges.gitter.im/eclipse/ditto.svg)](https://gitter.im/eclipse/ditto?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![License](https://img.shields.io/badge/License-EPL%202.0-green.svg)](https://opensource.org/licenses/EPL-2.0)
 
-This repository contains client SDKs in different languages for [Eclipse Ditto](https://websites.eclipseprojects.io/ditto/).
+This repository contains client SDKs in different languages for [Eclipse Ditto](https://www.eclipse.org/ditto/).
 
 ## [Java](java/)