[libadwaita] meson: Use correct SPDX identifier

[Alexander Mikhaylenko <alexm src gnome org>]

commit 80a908bd5018ae45adefbe04d5942288aa23d3ae
Author: Maximiliano Sandoval R <msandova protonmail com>
Date:   Mon Jul 26 14:16:02 2021 +0200

    meson: Use correct SPDX identifier

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 23f33ebf..b531964d 100644
--- a/meson.build
+++ b/meson.build
@@ -1,6 +1,6 @@
 project('libadwaita', 'c',
           version: '1.0.0-alpha.2',
-          license: 'LGPL-2.1+',
+          license: 'LGPL-2.1-or-later',
     meson_version: '>= 0.53.0',
   default_options: [ 'warning_level=1', 'buildtype=debugoptimized', 'c_std=gnu11' ],
 )