Android Gradle Plugin 9.0.0 upgrade notes

Version 9.0.0 of the Android Gradle Plugin brings in a lot of breaking changes, most of which are documented with clear upgrade paths except the fact that Kotlin Multiplatform libraries now ship their Android artifacts without consumer keep rules included. This needs to be manually turned on to preserve the existing behavior:

android {
  consumerKeepRules {
    publish = true
    file("consumer-proguard-rules.pro")
  }
}