DUB: Only fetch and cache packages in dub.json without running build

[Clinton]

On Tuesday, 10 April 2018 at 13:50:38 UTC, Clinton wrote:
> Hi all,
>
> I'm setting up a CircleCI config for my project. Right now I'm 
> trying to cache dependencies before running builds. This way I 
> can run "dub build --nodeps" immediately after the packages are 
> cached to avoid extra network calls and speed it up.
>
> [...]

Thanks. That's a good idea.

It would be great to have "dub fetch --all" or something like 
that to fetch all packages from the project dub.json.