Fix the screenshot in the project description

SandroMachado · SandroMachado · commit d4406657b043 · 2016-05-18T22:41:20.000+01:00
diff --git a/messaging/README.md b/messaging/README.md
@@ -50,7 +50,7 @@ Use Firebase console to send FCM messages to device or emulator.
 
 Screenshots
 -----------
-<img src="app/src/main/fcm-sample.png" height="534" width="300"/>
+<img src="app/src/screen.png" height="534" width="300"/>
 
 Support
 -------
