Skip Plugin Exceution for POM Projects

It's quite common to have a multi module project with a parent project
that has POM packaging. It would be quite convenient if the
kotlin-maven-plugin could be configured there instead of in each module.
Currently this is not possible because the plugin tries to execute on
POM projects with fails.

 - skip execution on POM projects

libraries/tools/kotlin-maven-plugin/pom.xml

@@ -25,6 +25,11 @@
             <artifactId>maven-plugin-api</artifactId>
             <version>${maven.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.maven</groupId>
+            <artifactId>maven-core</artifactId>
+            <version>${maven.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.jetbrains.kotlin</groupId>
             <artifactId>kotlin-compiler</artifactId>