Remove <span> tags from the message (#462)

src/background/utils/update.js

@@ -41,7 +41,7 @@ function doCheckUpdate(script) {
   };
   const doUpdate = () => {
     if (!downloadURL) {
-      update.message = `<span class="new">${i18n('msgNewVersion')}</span>`;
+      update.message = i18n('msgNewVersion');
       sendMessageOrIgnore(res);
       return Promise.reject();
     }