build: set linux build tag on CNI networking
build: set linux build tag on CNI networking

CNI network configuration is currently only supported on Linux.
For now, add the linux build tag so that the deadcode linter does
not trip over unused CNI stuff on macOS.

dvusboy/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad,hashicorp/nomad,burdandrei/nomad,dvusboy/nomad,burdandrei/nomad,burdandrei/nomad,dvusboy/nomad,hashicorp/nomad,burdandrei/nomad,hashicorp/nomad,burdandrei/nomad,dvusboy/nomad,dvusboy/nomad,hashicorp/nomad,burdandrei/nomad,hashicorp/nomad,hashicorp/nomad