Make Maven Spotless plugin format Kotlin source code

How do I get the Spotless Maven plugin to format all Kotlin source files?

<plugin>
    <groupId>com.diffplug.spotless</groupId>
    <artifactId>spotless-maven-plugin</artifactId>
    <executions>
        <execution>
            <id>spotless-apply</id>
            <phase>compile</phase>
            <configuration>
                <kotlin>
                    <ktlint/>
                </kotlin>
            </configuration>
            <goals>
                <goal>apply</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Not sure why your current configuration doesn't work, maybe its because the config is inside the execution block? If you move it up one level and then replace the apply with check it will work.

<plugin>
    <groupId>com.diffplug.spotless</groupId>
    <artifactId>spotless-maven-plugin</artifactId>
    <configuration>
        <kotlin>
            <ktlint />
        </kotlin>
    </configuration>
    <executions>
        <execution>
            <phase>compile</phase>
            <goals>
                <goal>check</goal>
            </goals>
        </execution>
    </executions>
</plugin>