[BUG] Cannot add extension with name 'googleServices', as there is an extension already registered with that name

[nikolleto]

Here is an issue in your build.gradle plugin: you are always applying plugin 'com.google.gms.googleservices.GoogleServicesPlugin' despite it can be added by another library before your gradle plugin is applied. When I'm building an application using 'cordova run android', I'm getting an error
"Cannot add extension with name 'googleServices', as there is an extension already registered with that name".

Please, take a look at my PR: #281