Use vendoring for backward compatibility
The switch of the Madon library to Go modules breaks builds with
Go version < 1.11 since the import path now contains "v2".
This patch adds vendoring so that it can still build with those
versions.
Let's try to re-enable Travis builds with Go v1.8-1.11...
version: '{build}'
clone_folder: C:\gopath\src\github.com\spf13\afero
environment:
GOPATH: C:\gopath
build_script:
- cmd: >-
go version
go env
go get -v github.com/spf13/afero/...
go build github.com/spf13/afero
test_script:
- cmd: go test -race -v github.com/spf13/afero/...