gradle-maven-publish-plugin: mavenPublish not found

I tried to change the default Sonatype host using this code snippet (in my build.gradle.kts):

allprojects {
    plugins.withId("com.vanniktech.maven.publish") {
        mavenPublish {
            sonatypeHost = SonatypeHost.S01
        }
    }
}

However, both mavenPublish and sonatypeHost cannot be found.