replace docker/docker with moby/moby

[johnstcn]

Reduce the number of dependencies and dependabot PRs and just use the moby/moby library for our unit tests instead of docker/docker.

          @johnstcn can we replace this with `moby/moby`?

for context: https://codercom.slack.com/archives/CJURPL8DN/p1722582536141789

Originally posted by @matifali in #6 (comment)

[johnstcn]

Apparently moby/moby is discouraged in favour of docker/docker.