internal/rosa: flags for toolchain-dependent artifact

This is much cleaner to add extra flags to.

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

internal/rosa/meson.go

@@ -7,7 +7,7 @@ func (t Toolchain) newMeson() pkg.Artifact {
 		version  = "1.10.1"
 		checksum = "w895BXF_icncnXatT_OLCFe2PYEtg4KrKooMgUYdN-nQVvbFX3PvYWHGEpogsHtd"
 	)
-	return t.New("meson-"+version, false, []pkg.Artifact{
+	return t.New("meson-"+version, 0, []pkg.Artifact{
 		t.Load(Python),
 		t.Load(Setuptools),
 	}, nil, nil, `