Remove **/*.java filter on added "sources as resources"

This better aligns with source:jar-no-fork behavior, and gwt:devmode
and gwt:codeserver behavior, and gwt:compile in gwt-app projects, that
directly put the source roots in the classpath (i.e. without filter).

src/main/java/net/ltgt/gwt/maven/AbstractSourcesAsResourcesMojo.java

@@ -5,11 +5,9 @@
 import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.project.MavenProject;
 
-import java.util.Collections;
 import java.util.List;
 
 public abstract class AbstractSourcesAsResourcesMojo extends AbstractMojo {
-  private static final List<String> JAVA_SOURCES = Collections.singletonList("**/*.java");
 
   @Parameter(defaultValue = "${project}", required = true, readonly = true)
   protected MavenProject project;
@@ -36,7 +34,6 @@ protected boolean checkResource(String sourceRoot) {
   protected Resource createResource(String resourceDirectory) {
     Resource resource = new Resource();
     resource.setDirectory(resourceDirectory);
-    resource.setIncludes(JAVA_SOURCES);
     return resource;
   }