Allow the artifact type to be changed

At current time the type generated by this plugin is hard coded:
AbstractSourceJarMojo line 177:
projectHelper.attachArtifact( project, "java-source", getClassifier(), outputFile );

If this "java-source" is moved to some getType it will allow me to extends this abstract class instead of duplicating this source.

Then I use org.ops4j.maven-inherit-plugin.

I can provide patch if required.

VELO