[aerogear-cordova-push] - Update the version of com.google.gms:google-services dependency

Update the version of the dependence com.google.gms.google-services to 3.1.0

Motivation

Unable to install aerogear-cordova-push plugin and the cordova-plugin-firebase in the same project. Shows that it is caused because of the version of com.google.gms.google-services used in the aerogear-cordova-push which is older than the version used in the cordova-plugin-firebase.

The cordova-plugin-firebase has a known issue, "Failed to apply plugin [id 'com.google.gms.google-services']", which shows quite common and will happen if you have more than one plugin using different versions of the dependence 'com.google.android.gms:play-services-gcm'. Check the google search about it.