Need "network_mode: host" when using docker-in-docker feature with compose

[davetapley]

When using this with docker-in-docker,
destinations won't be reachable from containers running in a Codespace
if you are using "dockerComposeFile": "docker-compose.yml" in devcontainer.json.

The workaround is to set network_mode: host in your docker-compose.yml.

---

A good test is running $ route -n, if you don't see this ⬇️ in the parent container then it won't work.

172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0