Try annotating as outputfiles too

Author: ZacSweers

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessTask.java

@@ -34,6 +34,7 @@
 import org.gradle.api.GradleException;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
+import org.gradle.api.tasks.OutputFiles;
 import org.gradle.api.tasks.TaskAction;
 import org.gradle.api.tasks.incremental.IncrementalTaskInputs;
 
@@ -118,6 +119,7 @@ public void setTarget(Iterable<File> target) {
 
 	/** Internal use only. */
 	@InputFiles
+	@OutputFiles
 	@Deprecated
 	public Iterable<File> getInternalTarget() {
 		// used to combine the special cache file and the real target