fix: symbolize_keys -> deep_symbolize_keys

lib/tallty_import_export/export.rb

@@ -307,7 +307,7 @@ module TalltyImportExport
     end
 
     def handle_select(data, origin_header, **opts)
-      header = origin_header.symbolize_keys
+      header = origin_header.deep_symbolize_keys
       if header[:select].present?
         select_option = header[:select].find { |option| option[:value].to_s == data.to_s }
         select_option.present? ? select_option[:label] : data