我正在尝试在我的 Ubuntu 18.04 上安装 Docker，但出现此错误：
The following packages have unmet dependencies:
docker-ce : Depends: containerd.io (>= 1.2.2-3) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
我该怎么做才能解决它？
你必须安装 containerd 包，这就是我解决它的方法。
$ curl -O https://download.docker.com/linux/ubuntu/dists/bionic/pool/edge/amd64/containerd.io_1.2.2-3_amd64.deb
$ sudo apt install ./containerd.io_1.2.2-3_amd64.deb