Gradle - "enforceUniquePackageName" deprecated with version 3.0.0+?

android {
    enforceUniquePackageName = false
}

"enforceUniquePackageName" works with the gradle version:

dependencies {
    classpath 'com.android.tools.build:gradle:2.3.1'
}

However, if I change the gradle version to 3.0.0

dependencies {
    classpath 'com.android.tools.build:gradle:3.0.0-alpha9'
}

I get:

Could not set unknown property 'enforceUniquePackageName' for object of type com.android.build.gradle.AppExtension. Open File

If 'enforceUniquePackageName' property is deprecated, then what would be the alternative option?