https://blog.callr.tech/migrating-from-dep-to-go-1.11-modules/
- move your code outside of GOPATH
- go mod init [module path]: this will import dependencies from Gopkg.lock.
- go mod tidy: this will remove unnecessary imports, and add indirect ones.
- rm -fr vendor/
- go build: is everthing ok?
- rm -f Gopkg.lock Gopkg.toml
- git commit -m 'chore(dep): migrated from dep to Go 1.11 modules'
go clean -modcache