Add cache mutex TTL

Author: marickvantuil

tests/TaskHandlerTest.php

@@ -156,7 +156,7 @@ public function it_prevents_overlapping_if_the_command_is_scheduled_without_over
         $command = ConsoleApplication::formatCommandString('test:command');
         $mutex = 'framework'.DIRECTORY_SEPARATOR.'schedule-'.sha1($expression.$command);
 
-        cache()->add($mutex, true);
+        cache()->add($mutex, true, 60);
 
         $this->taskHandler->handle();