Fix the npm/yarn install for mac users

[qboot]

Most of our mac users don't use anymore Dinghy but have still some troubles with running yarn / webpack on the Docker stack.

This change allow every mac users to execute npm/yarn commands on their host instead of within docker, regardless of if they are using Dinghy or Docker Desktop.

[lyrixx]

If we go this way, let's remove the dinghy notion an remplace it with macos, or at least add a global configuration variable macos thats is equals to dinghy or macos ? WDYT?

And about the feature : I don't have any inputs, I don't use mac OS.

Last note: please add an entry in the CHANGELOG.md, thanks

[qboot]

I'm not a big fan of removing the dinghy notion yet, it would be a breaking change for the users still using it.
And there is still specific code here: https://github.com/jolicode/docker-starter/blob/main/tasks.py#L44-L48

[lyrixx]

Perfect thanks