每当我尝试在我的 ubuntu 服务器 18.04 上安装 phpmyadmin 时，我都会收到以下错误
sudo apt install phpmyadmin php-mbstring php-gettext
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package phpmyadmin
E: Unable to locate package php-mbstring
E: Unable to locate package php-gettext
我发现的大多数线程都建议使用 apt 重新更新和升级，但这样做没有任何作用，而且我在第四行也收到了该错误
Err:5 http://ppa.launchpad.net/nijel/phpmyadmin/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Hit:6 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:7 http://download.webmin.com/download/repository sarge Release
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/nijel/phpmyadmin/ubuntu bionic Release' does not have a Release file.
有人可以帮忙吗？