[gnome-control-center/wip/jimmac/flatpak-manifest] flatpak: Build gnome-backgrounds form main branch

[Jakub Steiner <jimmac src gnome org>]

commit a46359595ab9cfee401ef0d0b0cf067ccfee75ff
Author: Jakub Steiner <jimmac gmail com>
Date:   Wed Feb 2 13:09:59 2022 +0100

    flatpak: Build gnome-backgrounds form main branch

 build-aux/flatpak/org.gnome.Settings.json | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/build-aux/flatpak/org.gnome.Settings.json b/build-aux/flatpak/org.gnome.Settings.json
index 6008b2ef0..918d920d2 100644
--- a/build-aux/flatpak/org.gnome.Settings.json
+++ b/build-aux/flatpak/org.gnome.Settings.json
@@ -638,6 +638,7 @@
             "sources" : [
                 {
                     "type" : "git",
+                    "branch": "main",
                     "url" : "https://gitlab.gnome.org/GNOME/gnome-backgrounds.git";
                 }
             ]