Ubuntu18.04安装shadowsocks-qt5

网上的教程一般都这样写

sudo add-apt-repository ppa:hzwhuang/ss-qt5
sudo apt-get update
sudo apt-get install shadowsocks-qt5

但执行第一步就报错了，如下

sudo add-apt-repository ppa:hzwhuang/ss-qt5
 Shadowsocks-Qt5 is a cross-platform Shadowsocks GUI client.

Shadowsocks is a lightweight tool that helps you bypass firewall(s).

This PPA mainly includes packages for Shadowsocks-Qt5, which means it also includes libQtShadowsocks packages.
 更多信息： https://launchpad.net/~hzwhuang/+archive/ubuntu/ss-qt5
按 [ENTER] 继续或 Ctrl-c 取消安装。

命中:1 http://mirrors.aliyun.com/ubuntu bionic InRelease
忽略:2 http://dl.google.com/linux/chrome/deb stable InRelease                  
命中:3 http://mirrors.aliyun.com/ubuntu bionic-updates InRelease               
命中:4 https://packages.microsoft.com/repos/vscode stable InRelease            
忽略:5 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 InRelease    
命中:6 http://mirrors.aliyun.com/ubuntu bionic-backports InRelease             
命中:7 http://archive.ubuntu.com/ubuntu bionic InRelease                       
命中:8 http://dl.google.com/linux/chrome/deb stable Release                    
忽略:10 http://ppa.launchpad.net/hzwhuang/ss-qt5/ubuntu bionic InRelease       
命中:11 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 Release
命中:12 http://mirrors.aliyun.com/ubuntu bionic-security InRelease             
错误:14 http://ppa.launchpad.net/hzwhuang/ss-qt5/ubuntu bionic Release         
  404  Not Found [IP: 91.189.95.83 80]
正在读取软件包列表... 完成
E: 仓库 “http://ppa.launchpad.net/hzwhuang/ss-qt5/ubuntu bionic Release” 没有 Release 文件。
N: 无法安全地用该源进行更新，所以默认禁用该源。
N: 参见 apt-secure(8) 手册以了解仓库创建和用户配置方面的细节。

原因是ppa:hzwhuang/ss-qt5 并没有18.04版本的源

解决办法是将bionic (18.04版本代号)改成xenial（16.04版本代号）

如下

sudo vim /etc/apt/sources.list.d/hzwhuang-ubuntu-ss-qt5-bionic.list

  deb http://ppa.launchpad.net/hzwhuang/ss-qt5/ubuntu xenial main
  # deb-src http://ppa.launchpad.net/hzwhuang/ss-qt5/ubuntu xenial main

接下来update就可以了