Merge pull request #24 from erlangp/patch-5

Update laravel-fcm.php

Author: sayaamirul

resources/config/laravel-fcm.php

@@ -7,5 +7,6 @@
      * Change to yours
      */
 
-    'server_key' => ''
+    'server_key' => env('FCM_SERVER_KEY', ''),
+
 ];