dep: docker engine API compatibility outdated #8
Description
it looks like our pin of docker v20 gives us docker engine API v1.41:
https://github.com/picoCTF/cmgr/blob/89c45a6bab8bc9032f9235231eeab11f5c289826/go.mod#L10C2-L10C49
Connections to remote challenge servers with docker-ce @ latest (v29) will fail with complaint:
Error response from daemon: client version 1.41 is too old. Minimum supported API version is 1.44, please upgrade your client to a newer version
FWIW docker v28 still works, so short term deployments can just pin that package until this dep (and maybe any others) get updated