fix(repo): update devcontainer defaults to use bundled postgres

[Hegi]

Not much to add here. After I pulled down the repo vscode suggested to open it in a devcontainer. When I did the thing wasn't working. Because of how the compose file is configured, I just renamed localhost to db plus updated the relevant environment variables and voila.

[Hegi]

Any reason this isn't merged in just yet? :)

[diced]

Any reason this isn't merged in just yet? :)

no idea 💀 probably forgot