Switch demo back to using latest stable version

Author: nene

static/index.html

@@ -201,7 +201,7 @@ <h3 style="margin: 0.5rem 0">Options</h3>
 
     <script
       type="text/javascript"
-      src="https://unpkg.com/sql-formatter@beta/dist/sql-formatter.min.js"
+      src="https://unpkg.com/sql-formatter@latest/dist/sql-formatter.min.js"
     ></script>
     <script type="text/javascript" src="index.js"></script>
   </body>