fix: reject / as the -v destination in nerdctl run for Docker com…

[haytok]

…patibility

In the current implementation, when specifying / as the destination of the -v option in the nerdctl run command, the following error occurs but the container is created.

> sudo nerdctl run -d --name nginx -v ./:/ nginx
FATA[0000] failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: unable to apply apparmor profile: apparmor failed to apply profile: open /proc/thread-self/attr/exec: no such file or directory

> sudo nerdctl ps -a
CONTAINER ID    IMAGE                             COMMAND                   CREATED          STATUS     PORTS    NAMES
0f880e0e68f8    docker.io/library/nginx:latest    "/docker-entrypoint.…"    5 seconds ago    Created             nginx

However, in the same situation, Docker fails to create the container.

$ docker run -d --name stop -v ./:/ nginx
docker: Error response from daemon: invalid volume specification: '/Users/haytok/workspace:/': invalid mount config for type "bind": invalid specification: destination can't be '/'

$ docker ps -a
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

Therefore, this commit fixes the behavior so that the container creation fails when / is specified as the destination of the -v option for compatibility with Docker.