[calls] metainfo: Replace deprecated GPL license identifier

[Evangelos Ribeiro Tzaras <devrtz src gnome org>]

commit a723a667679c09937d7cbcd5707fdce3a026984e
Author: Evangelos Ribeiro Tzaras <devrtz fortysixandtwo eu>
Date:   Tue Oct 19 19:37:26 2021 +0200

    metainfo: Replace deprecated GPL license identifier
    
    It is deprecated according to https://spdx.org/licenses/GPL-3.0+.html
    and GPL-3.0-or-later should be used instead.

 data/org.gnome.Calls.metainfo.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/data/org.gnome.Calls.metainfo.xml b/data/org.gnome.Calls.metainfo.xml
index 01158ea7..80c55348 100644
--- a/data/org.gnome.Calls.metainfo.xml
+++ b/data/org.gnome.Calls.metainfo.xml
@@ -2,7 +2,7 @@
 <component type="desktop-application">
     <id>org.gnome.Calls</id>
     <metadata_license>CC0-1.0</metadata_license>
-    <project_license>GPL-3.0+</project_license>
+    <project_license>GPL-3.0-or-later</project_license>
     <name>Calls</name>
     <summary>Make phone and SIP calls</summary>