[rygel] rygel: Add missing license identifier

[Jens Georg <jensgeorg src gnome org>]

commit 66b9dec8c4018e750ac571e54cbed9acb06aac2c
Author: Jens Georg <mail jensge org>
Date:   Thu May 12 19:59:55 2022 +0200

    rygel: Add missing license identifier

 src/rygel/application.vala | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/rygel/application.vala b/src/rygel/application.vala
index 75c16f633..11d1eadc5 100644
--- a/src/rygel/application.vala
+++ b/src/rygel/application.vala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+//
 using Gee;
 using GUPnP;