Unable to locate package ***
遇到这个问题直接尝试sudo apt-get update 和 sudo apt-get upgrade 一般可以解决，
但是执行之后出现源的问题，访问ubuntu 官方源link time out.
Cannot initiate the connection to cn.archive.ubuntu.com:80 (2001:67c:1562::18)
1、划重点： 直接换源
注释掉Ubuntu 官方deb 链接，添加国内源链接
sudo vim /etc/apt/source.list
添加国内原链接：阿里源或者其他国内源
阿里源：
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
2、重新update 和 upgrade，且重新安装
sudo apt-get update
sudo apt-get upgrade
