hotfix input can be null

AlboCode · AlboCode · commit 711a1a34eabd · 2024-01-04T00:17:19.000+09:00
diff --git a/src/Model/Why.php b/src/Model/Why.php
@@ -4,7 +4,7 @@
 
 class Why
 {
-    public string $input;
+    public ?string $input;
 
     /**
      * @var null|array<string, mixed>
