Issue #394: use sonar api version 8.9.0 for full 8.9.x compatibility

Author: muhlba91

pom.xml

@@ -94,7 +94,7 @@
 
   <properties>
     <checkstyle.version>9.2.1</checkstyle.version>
-    <sonar.version>8.9.3.48735</sonar.version>
+    <sonar.version>8.9.0.43852</sonar.version>
     <sonar-java.version>7.2.0.26923</sonar-java.version>
     <maven.checkstyle.plugin.version>3.1.2</maven.checkstyle.plugin.version>
     <maven.sevntu.checkstyle.plugin.version>1.40.0</maven.sevntu.checkstyle.plugin.version>