Ubuntu 升级 git，如何应对sudo add-apt-repository ppa:git-core/ppa卡死的情况

绕开代理 https://blog.csdn.net/m0_68734901/article/details/128411072

1. sudo -E add-apt-repository ppa:git-core/ppa
2. sudo apt-get update
3. sudo apt-get install git