Upgrade Travis Go to 1.12.x
Fixes Travis Windows build problem because go modules are enabled
by default in 1.12.x and don't need an environment variable to be
set.
language: go
go:
- - "1.11.x"
+ - "1.12.x"
os:
- linux
- osx
- windows
script:
- - env GO111MODULE=on make build
- - env GO111MODULE=on make test
+ - make build
+ - make test
