fix: preview url

Author: xlc-dev

src/template.html

@@ -31,11 +31,11 @@
     />
     <meta
       property="og:image"
-      content="https://xlc-dev.github.io/fssg/img/logo.png"
+      content="https://xlc-dev.github.io/fssg/static/img/logo.png"
     />
     <meta
       name="twitter:image"
-      content="https://xlc-dev.github.io/fssg/img/logo.png"
+      content="https://xlc-dev.github.io/fssg/static/img/logo.png"
     />
     <meta property="og:url" content="https://xlc-dev.github.io/fssg/" />
   </head>