Fix template generating invalid wg.yaml

Author: ynojima

working-groups/templates/wg.yaml.template

@@ -3,7 +3,7 @@ working-groups:
   {#for board in boards}
     - title: "{board.title}"
       board-url: "{board.url}"
-      short-description: {board.shortDescription.trim()}
+      short-description: "{board.shortDescription.trim()}"
       readme: |
         {board.getIndentedReadme().raw}
       status: {board.getBadgeText()}