updated readme

Author: clausnagel

README.md

@@ -47,9 +47,9 @@ previous release of the 3D City Database Importer/Exporter under Apache License
 
 Latest release
 --------------
-The latest stable release of the 3D City Database Importer/Exporter is 5.5.1.
+The latest stable release of the 3D City Database Importer/Exporter is 5.5.2.
 
-Download the software [here](https://github.com/3dcitydb/importer-exporter/releases/download/v5.5.1/3DCityDB-Importer-Exporter-5.5.1.zip).
+Download the software [here](https://github.com/3dcitydb/importer-exporter/releases/download/v5.5.2/3DCityDB-Importer-Exporter-5.5.2.zip).
 Previous releases are available from the [releases section](https://github.com/3dcitydb/importer-exporter/releases).
 
 System requirements