update readme

Author: jogibear9988

README.md

@@ -14,4 +14,8 @@ simple run
     npm run release
 
 then you need to go to github and create a release from the uploaded tag.
-this will then create a npm package via github action.
+this will then create a npm package via github action.
+
+# copyright notice
+Sweet Home 3D JS Viewer, Copyright (c) 2005-2023 Emmanuel PUYBARET / eTeks. 
+Distributed under GNU General Public License