1 镜像clone老仓库
git clone <upstream-repo-url/repo.git> --mirror
2 创建一个新的空仓库
3 将镜像push到新的仓库
git remote add <your-remote-name> <your-remote-url/repo.git>
git push <your-remote-name> --mirror
git clone <upstream-repo-url/repo.git> --mirror
git remote add <your-remote-name> <your-remote-url/repo.git>
git push <your-remote-name> --mirror