[Build Service] Custom fields in manifest.xml for Android builds

I have come across a case where I need to provide custom values to the Android APK manifest.xml, is there a way to do that using AppGyver?

My use-case is that I’d like to provide some value for the push notification icon provided by firebase because the default is a white, blank icon.

Some Google search suggests that I need to add the following lines to my manifest.xml file.

 <meta-data
        android:name="com.google.firebase.messaging.default_notification_icon"
        android:resource="@drawable/ic_stat_ic_notification" />
  <meta-data
        android:name="com.google.firebase.messaging.default_notification_color"
        android:resource="@color/colorAccent" />