[gnome-build-meta] gnome-session.bst: Update for gnome-session master→main branch rename

[Ray Strode <halfline src gnome org>]

commit 9c3e3960ea2623fd21ac557d7d9939ae3bca59d1
Author: Ray Strode <halfline gmail com>
Date:   Wed Sep 29 19:26:15 2021 +0000

    gnome-session.bst: Update for gnome-session master→main branch rename
    
    gnome-session now uses main instead of master for its main branch.

 elements/core/gnome-session.bst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/elements/core/gnome-session.bst b/elements/core/gnome-session.bst
index 6f1a5d80d..1705cc9ac 100644
--- a/elements/core/gnome-session.bst
+++ b/elements/core/gnome-session.bst
@@ -3,7 +3,7 @@ kind: meson
 sources:
 - kind: git_tag
   url: gitlab_gnome_org:GNOME/gnome-session.git
-  track: master
+  track: main
 
 build-depends:
 - freedesktop-sdk.bst:components/docbook-xsl.bst