Fix enforcer plugin failure in sonar profile on Java 8

The sonar profile was overriding jdk.version to 11, causing the
maven-enforcer-plugin's requireJavaVersion rule to reject Java 8.
Remove the override so the default jdk.version (1.8) is used.

Author: vpaturet

pom.xml

@@ -701,7 +701,6 @@
             </activation>
 
             <properties>
-                <jdk.version>11</jdk.version>
                 <sonar-maven-plugin.version>3.9.1.2184</sonar-maven-plugin.version>
             </properties>