internal/rosa/stage0: add arm64 tarball

This took far longer to complete because the aarch64 development machine is much slower.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/stage0.go

@@ -57,6 +57,8 @@ func NewStage0() pkg.Artifact {
 		switch runtime.GOARCH {
 		case "amd64":
 			seed = "tqM1Li15BJ-uFG8zU-XjgFxoN_kuzh1VxrSDVUVa0vGmo-NeWapSftH739sY8EAg"
+		case "arm64":
+			seed = "CJj3ZSnRyLmFHlWIQtTPQD9oikOZY4cD_mI3v_-LIYc2hhg-cq_CZFBLzQBAkFIn"
 
 		default:
 			panic("unsupported target " + runtime.GOARCH)