koji: use none container arch in CGImport metadata

osbuild runs directly on the host, there's no intermediate container,
therefore we should set the container type to none.

As suggested by Brew maintainers Tomáš Kopeček and Lubomír Sedlář.

cmd/osbuild-worker/main.go

@@ -264,7 +264,7 @@ func RunJob(job worker.Job, store string, kojiServers map[string]koji.GSSAPICred
 						Version: "1",
 					},
 					Container: koji.Container{
-						Type: "nspawn",
+						Type: "none",
 						Arch: common.CurrentArch(),
 					},
 					Tools: []koji.Tool{},