They've started to think about it: https://groups.google.com/forum/#!topic/golang-dev/nMWoEAG55...
Re:Cross compilation just got better in Go 1.5
by stock_toaster on Monday March 02, 2015 @10:55PM
(#9136014)
I don't believe so. Your options are still pretty much:
(a) vendoring with something like godep[1], or (b) point in time scm fetching with something like gpm[2].
Did they ever figure out dependency versioning?