tweak: friendlier cli message

Author: g105b

composer.lock

@@ -8,6 +8,7 @@
 use Gt\Cli\Parameter\Parameter;
 use Gt\Cli\Stream;
 use Gt\Cron\CronException;
+use Gt\Cron\CrontabNotFoundException;
 use Gt\Cron\FunctionExecutionException;
 use Gt\Cron\RunnerFactory;
 use Gt\Cron\ScriptExecutionException;
@@ -27,6 +28,10 @@ public function run(?ArgumentValueList $arguments = null):void {
 				$filename
 			);
 		}
+		catch(CrontabNotFoundException) {
+			$this->stream->writeLine("Skipping cron as there is no crontab file.");
+			return;
+		}
 		catch(CronException $exception) {
 			$this->stream->writeLine(
 				$exception->getMessage(),