Thanks.
This works for me:
\platforms\android\project.properties
cordova.system.library.5=com.google.firebase:firebase-core:16.0.8
cordova.system.library.6=com.google.firebase:firebase-messaging:17.5.0
cordova.system.library.7=com.google.firebase:firebase-crash:+
cordova.system.library.8=com.google.firebase:firebase-config:16.4.1
