fix：正确修改rss生成的icon

Author: 88lin

lib/utils/rss.js

@@ -54,7 +54,7 @@ export async function generateRss(props) {
     description: DESCRIPTION,
     link: `${LINK}/${SUB_PATH}`,
     language: LANG,
-    favicon: `${LINK}/favicon.png`,
+    favicon: `${LINK}/favicon.svg`,
     copyright: `All rights reserved ${year}, ${AUTHOR}`,
     author: {
       name: AUTHOR,