我遇到以下错误，网站上似乎缺少发布文件：
Ign:1 http://old-releases.ubuntu.com/ubuntu eoan InRelease
Ign:2 http://old-releases.ubuntu.com/ubuntu eoan-updates InRelease
Ign:3 http://old-releases.ubuntu.com/ubuntu eoan-security InRelease
Err:4 http://old-releases.ubuntu.com/ubuntu eoan Release
404 Not Found [IP: 91.189.88.248 80]
Err:5 http://old-releases.ubuntu.com/ubuntu eoan-updates Release
404 Not Found [IP: 91.189.88.248 80]
Err:6 http://old-releases.ubuntu.com/ubuntu eoan-security Release
404 Not Found [IP: 91.189.88.248 80]
Reading package lists... Done
E: The repository 'http://old-releases.ubuntu.com/ubuntu eoan Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for …