AiiDAlab launch sometimes fails to communicate with Docker client.

The problem appears with the latest versions of the Docker desktop.

To fix one should go to advanced settings and check the case: “Allow the default Docker socket to be used (requires password)”. This action will create a socket file at `/var/run/docker.sock`.

The actual function that raises the error is `docker.from_env()`:

```python
import docker
docker.from_env()
```

The problem should be fixed upstream, but I wanted to report it here.