internal/pkg: exclusive artifacts

This alleviates scheduler overhead when curing many artifacts.

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

internal/rosa/rsync.go

@@ -7,7 +7,7 @@ func (t Toolchain) newRsync() pkg.Artifact {
 		version  = "3.4.1"
 		checksum = "VBlTsBWd9z3r2-ex7GkWeWxkUc5OrlgDzikAC0pK7ufTjAJ0MbmC_N04oSVTGPiv"
 	)
-	return t.New("rsync-"+version, []pkg.Artifact{
+	return t.New("rsync-"+version, false, []pkg.Artifact{
 		t.Load(Make),
 	}, nil, nil, `
 cd "$(mktemp -d)"