We expect the Go team to work on this situation and at least finalize the proposed change in this PR.
Also, for what it’s worth, the Go team is not maintaining, supporting, or pushing changes into Dep. Personally, I think that PR is a good idea, but whether to merge it is up to Sam Boyer and the other Dep contributors.
And of course even if that PR is merged, any other pre-modules vendoring solutions would still be broken unless you use a v2/ subdirectory.