Invalid Crashlytics API Key error when upgrading to Android Gradle Plugin 3.3.0

This is a known incompatibility with the v4.1.0 plugin and AGP 3.3 alpha versions. The workaround is to downgrade to v4.0.2 of the google-services plugin. More discussion and details may be found here: https://github.com/firebase/quickstart-android/pull/661.

google-services 4.2.0 also fixes the problem.

platforms/android/build.gradle