Remove used tab instead of four spaces

app/Export/TaskExport.php

@@ -70,7 +70,7 @@ class TaskExport extends Base
             tasks.date_started,
             tasks.time_estimated,
             tasks.time_spent,
-			tasks.reference
+            tasks.reference
             FROM tasks
             LEFT JOIN users ON users.id = tasks.owner_id
             LEFT JOIN users AS creators ON creators.id = tasks.creator_id
@@ -144,7 +144,7 @@ class TaskExport extends Base
             e('Start date'),
             e('Time estimated'),
             e('Time spent'),
-			e('Reference'),
+            e('Reference'),
         );
     }
 }