使用sudo apt update更新时遇到问题：

使用deepin镜像源更新提示没有 E: 仓库 “https://packages.mkacg.com panda InRelease” 没有数字签名

命中:1 https://community-packages.deepin.com/deepin apricot InRelease命中:2 https://community-packages.deepin.com/driver driver InRelease
命中:3 https://community-packages.deepin.com/printer eagle InRelease
命中:4 https://home-store-img.uniontech.com/220826183702208/appstore deepin InRelease
错误:5 https://packages.mkacg.com panda InRelease
530 [IP: 172.67.173.90 443]
正在读取软件包列表... 完成
E: 无法下载 https://packages.mkacg.com/dists/panda/InRelease 530 [IP: 172.67.173.90 443]
E: 仓库 “https://packages.mkacg.com panda InRelease” 没有数字签名。
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。

更换阿里镜像源后：

获取:1 http://mirrors.aliyun.com/deepin apricot InRelease [13.6 kB]
命中:2 https://community-packages.deepin.com/driver driver InRelease
命中:3 https://community-packages.deepin.com/printer eagle InRelease
忽略:5 http://mirrors.aliyun.com/deepin apricot/main i386 Packages
命中:4 https://home-store-img.uniontech.com/220826183702208/appstore deepin InRelease
忽略:6 http://mirrors.aliyun.com/deepin apricot/main amd64 Packages
忽略:7 http://mirrors.aliyun.com/deepin apricot/contrib i386 Packages
忽略:8 http://mirrors.aliyun.com/deepin apricot/contrib amd64 Packages
忽略:9 http://mirrors.aliyun.com/deepin apricot/non-free amd64 Packages
忽略:10 http://mirrors.aliyun.com/deepin apricot/non-free i386 Packages
获取:5 http://mirrors.aliyun.com/deepin apricot/main i386 Packages [14.8 MB]
错误:11 https://packages.mkacg.com panda InRelease
530 [IP: 172.67.173.90 443]
获取:6 http://mirrors.aliyun.com/deepin apricot/main amd64 Packages [14.9 MB]
获取:7 http://mirrors.aliyun.com/deepin apricot/contrib i386 Packages [77.2 kB]
获取:8 http://mirrors.aliyun.com/deepin apricot/contrib amd64 Packages [83.4 kB]
获取:9 http://mirrors.aliyun.com/deepin apricot/non-free amd64 Packages [216 kB]
获取:10 http://mirrors.aliyun.com/deepin apricot/non-free i386 Packages [175 kB]
正在读取软件包列表... 完成
E: 无法下载 https://packages.mkacg.com/dists/panda/InRelease 530 [IP: 172.67.173.90 443]
E: 仓库 “https://packages.mkacg.com panda InRelease” 没有数字签名。
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。