No static method metafactory

Try to switch to Java 8 compatibility mode, for proper de-sugaring of some library:

android {

    ...
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = "1.8"
    }
}

Besides, Google JSON API might rather need the GsonConverterFactory.