add AllowDynamicProperties for XBase\Header\Column::* properties to fix deprecation warnings (#127)

Author: Haehnchen

src/Header/Column.php

@@ -14,6 +14,7 @@
  * @property int $mdxFlag
  * @property int $nextAI
  */
+#[\AllowDynamicProperties]
 class Column
 {
     /** @var string */