language: go

go:
  - 1.3
  - 1.5
  - tip

language: go

go:
  - 1.5.x
  - 1.6.x
  - 1.7.x
  - 1.8.x
  - master

Update to stop testing against "old" golang.
Update to stop testing against "old" golang.

We test 1.5 and newer only.  Arguably we could probably stop testing
anything older than 1.7, but some folks will still be using older
versions of golang.  Note that 1.3 is definitely busted.
