Update README.md NB about AI add-on statement.

README.md

@@ -3,7 +3,8 @@
 
 
 このリポジトリでは、Adobe IllustratorでGISデータを読み込みためのソフトウェア[`PlugX-QGIS`](https://chiri.com/products/plugx/qgisai)向けに、GISデータをエクスポートするためのQGISプラグインを管理します。<br><br>
-This plugin exports GIS data in a folder, which can be read and imported into Adobe Illustrator using an add-on called [`PlugX-QGIS`](https://chiri.com/products/plugx/qgisai).
+This plugin exports GIS data in a folder, which can be read and imported into Adobe Illustrator using an add-on called [`PlugX-QGIS`](https://chiri.com/products/plugx/qgisai).<br><br>
+NB: Despite QGIS plugin is free to use, Adobe Illustrator PlugX add-on is NOT a freeware. Please check details [here](https://chiri.com/products/plugx/qgisai).
 
 ## 本プラグインとPlugX-QGISの連携方法について / How to use this plugin with PlugX-QGIS