add kotlin source code to task sourcesJar

build.gradle

@@ -163,7 +163,7 @@ subprojects {
     //noinspection GroovyAssignabilityCheck
     task sourcesJar(type: Jar) {
         archiveClassifier = 'sources'
-        from sourceSets.main.allJava
+        from sourceSets.main.allSource
     }
 
     javadoc {