fix headers with group_by

lib/tallty_import_export/export.rb

@@ -38,7 +38,6 @@ module TalltyImportExport
         workbook = pack.workbook
 
         if @group_by.present?
-          @header = nil # 因为group_by的，基本上都是export_header动态变化的，因此去掉选择
           if records.is_a?(Array)
             records.group_by { |record| record.send(@group_by)}.each do |key, group_records|
               @group_key = key

lib/tallty_import_export/version.rb

 module TalltyImportExport
-  VERSION = "1.0.13"
+  VERSION = "1.0.14"
 end