[gnome-characters/main] flatpak: Use `main` branch

[Christopher Davis <christopherdavis src gnome org>]

commit 2ccc931e924f336f10d1ed395d0e0311a0457048
Author: Christopher Davis <christopherdavis gnome org>
Date:   Sun Feb 20 12:33:10 2022 -0800

    flatpak: Use `main` branch

 build-aux/flatpak/org.gnome.Characters.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/build-aux/flatpak/org.gnome.Characters.json b/build-aux/flatpak/org.gnome.Characters.json
index 8c7d9d9..2be1bf0 100644
--- a/build-aux/flatpak/org.gnome.Characters.json
+++ b/build-aux/flatpak/org.gnome.Characters.json
@@ -52,7 +52,8 @@
             "sources" : [
                 {
                     "type" : "git",
-                    "url" : "https://gitlab.gnome.org/gnome/gnome-characters.git";
+                    "url" : "https://gitlab.gnome.org/gnome/gnome-characters.git";,
+                    "branch" : "main"
                 }
             ]
         }