Promote migration storage directory

Author: stevebauman

src/Filesystem/MigrationStorage.php

@@ -11,19 +11,14 @@
  */
 class MigrationStorage implements ReadinessInterface
 {
-    /**
-     * @var string
-     */
-    protected $directory;
-
     /**
      * Create a new migration storage instance.
      */
     public function __construct(
         protected Filesystem $filesystem,
-        ?string $directory = null
+        protected string $directory
     ) {
-        $this->directory = rtrim($directory ?? '', '/');
+        $this->directory = rtrim($directory, '/');
     }
 
     /**