cmd/mbf: enable output colouring

This respects the de facto standards, on top of checking stderr.

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

internal/rosa/rosa_test.go

@@ -58,11 +58,11 @@ func getCache(t *testing.T) *pkg.Cache {
 			ctx, buildTestCacheCancel = signal.NotifyContext(context.Background(),
 				syscall.SIGINT, syscall.SIGTERM)
 
-			msg := message.New(log.New(os.Stderr, "rosa: ", 0))
+			msg := message.New(log.New(os.Stderr, "\x1b[2mrosa: \x1b[0m", 0))
 			msg.SwapVerbose(true)
 
 			if buildTestCache, err = pkg.Open(ctx, msg, a, &pkg.CacheAttr{
-				Flags: pkg.CSuppressInit,
+				Flags: pkg.CSuppressInit | pkg.CColourOutput,
 			}); err != nil {
 				t.Fatal(err)
 			}