Jira plugin obfuscation

Hi!
I can’t figure it out how to obfuscate jira plugin that is written in kotlin.
I have the following plugin in my pom.xml.


> <plugin>
>                 <groupId>com.github.wvengen</groupId>
>                 <artifactId>proguard-maven-plugin</artifactId>
>                 <executions>
>                     <execution>
>                         <id>process-classes-with-proguard</id>
>                         <phase>package</phase>
>                         <goals>
>                             <goal>proguard</goal>
>                         </goals>
>                         <configuration>
>                             <obfuscate>true</obfuscate>
>                             <injar>${project.build.finalName}.jar</injar>
>                             <outjar>${project.build.finalName}-obfuscated.jar</outjar>
>                             <outputDirectory>${project.build.directory}</outputDirectory>
>                             <appendClassifier>false</appendClassifier>
>                             <addMavenDescriptor>false</addMavenDescriptor>
>                             <options>
>                                 <option>-allowaccessmodification</option>
>                                 <option>-dontshrink</option>
>                                 <option>-keepattributes *Annotation*</option>
>                                 <option>-keepattributes InnerClasses</option>
>                                 <option>-keepattributes Signature</option>
>                                 <option>-keep public interface * { *;}</option>
>                                 <option>-keep public class * </option>
>                                 <option>-dontwarn</option>
>                             </options>
>                             <libs>
>                                 <lib>${java.home}/lib/rt.jar</lib>
>                                 <lib>${java.home}/lib/jsse.jar</lib>
>                             </libs>
>                             <proguardVersion>5.2</proguardVersion>
>                         </configuration>
>                     </execution>
>                 </executions>
>             </plugin>

But when installing it i always have a lot of errors like

Invalid default: public abstract kotlin.annotation.AnnotationRetention kotlin.annotation.Retention.value()