Adds JavaDoc badge

Author: FrankSchnicke

README.md

@@ -1,3 +1,5 @@
+[![javadoc](https://javadoc.io/badge2/org.eclipse.basyx/basyx.sdk/javadoc.svg)](https://javadoc.io/doc/org.eclipse.basyx/basyx.sdk) 
+
 # Eclipse BaSyx Java SDK
 [![BaSyx Logo](https://www.eclipse.org/basyx/img/basyxlogo.png)](https://www.eclipse.org/basyx/)
 
@@ -28,4 +30,4 @@ Additionally, you can also find videos explaining the BaSyx middleware on youtub
 
 If you would like to contribute, please notice the [contribution guidelines](CONTRIBUTING.md). The overall process is described in the [Eclipse wiki](https://wiki.eclipse.org/BaSyx_/_Developer_/_Contributing).
 
-This GitHub project is migrated from the Eclipse infrastructure. For the archived history, see the [previous repository](https://git.eclipse.org/c/basyx/basyx.git/).
+This GitHub project is migrated from the Eclipse infrastructure. For the archived history, see the [previous repository](https://git.eclipse.org/c/basyx/basyx.git/).