Support for default build type/ flavor

buildTypes {
  debug {
    getIsDefault().set(true)
  }
  release {
  }
}
productFlavors {
  alpha {
    getIsDefault().set(true)
  }
  prod {
  }
}

https://proandroiddev.com/android-set-a-default-build-type-flavor-a1cdcd1c15fa