Task dependency gives deprecation warning in gradle 4

I have a task that depends on sub projects being “assembled” so that it can package subproject jar files.

The extract task line in this section:

getSubprojects().each {
extractTask.dependsOn it.getTasksByName(‘assemble’, true)

now throws the warning: “Gradle now uses separate output directories for each JVM language…”

The code seems to still work fine, what should I change to make it 4.0 “compliant”?