fix: support Gitea 28.0.0 mail templates

themes/horizon/mail/repo/release.tmpl

@@ -113,7 +113,7 @@
             {{if .Release.Attachments}}
               {{range .Release.Attachments}}
                 <li>
-                  <a href="{{.DownloadURL}}" target="_blank">{{.Name}} ({{.Size | FileSize}})</a>
+                  <a href="{{.DownloadURL}}" target="_blank">{{.Name}} ({{.Size | FormatByteSize}})</a>
                 </li>
               {{end}}
             {{end}}
@@ -166,4 +166,4 @@
     </table>
   </center>
 </body>
-</html>
+</html>