Update: Fixes issue with building due to new update of Google Play services https://github.com/arnesson/cordova-plugin-firebase/issues/610

fixFirebasePlugin.js

@@ -0,0 +1,14 @@
+module.exports = function(context) {
+	var fs = require('fs');
+	var path = require('path');
+
+	var rootdir = context.opts.projectRoot;
+
+	var platformDir = 'platforms/android';
+        //change the path to your external gradle file
+	var srcFile = path.join(rootdir, 'src/android/build-extras.gradle');
+	var destFile = path.join(rootdir, platformDir, 'build-extras.gradle');
+
+	console.log("copying "+srcFile+" to "+destFile);
+	fs.createReadStream(srcFile).pipe(fs.createWriteStream(destFile));
+}