我目前在我的计算机上运行 Debian Buster 作为测试。现在 Buster 已经稳定了，我应该如何更新我的系统？
具体来说，我如何配置/etc/apt/sources.list？
目前，它看起来像这样：
# deb cdrom:[Official Debian GNU/Linux Live 9.9.0 xfce 2019-04-27T10:47]/ stretch main
# deb cdrom:[Official Debian GNU/Linux Live 9.9.0 xfce 2019-04-27T10:47]/ stretch main
deb http://ftp.uk.debian.org/debian/ buster main
deb-src http://ftp.uk.debian.org/debian/ buster main
deb http://security.debian.org/debian-security/ buster/updates main
deb-src http://security.debian.org/debian-security/ buster/updates main
#stretch-updates, previously known as 'volatile'
deb http://ftp.uk.debian.org/debian/ buster-updates main
deb-src http://ftp.uk.debian.org/debian/ buster-updates main
当我运行时，sudo apt-get update我得到这个输出：
Ign:1 http://deb.debian.org/debian stretch InRelease
Get:2 http://security.debian.org/debian-security buster/updates InRelease [31.1 kB]
Get:3 http://ftp.uk.debian.org/debian buster InRelease [118 kB] …debian ×1