gnome-shell.bst: Bump gnome-shell to d067f6ca to fix PAYG dialog on login screen

Part-of: #220

Author: starnight

elements/core/gnome-shell.bst

@@ -6,7 +6,7 @@ sources:
 - kind: git_repo
   url: github:endlessm/gnome-shell.git
   track: 12-gnome-shell-48.4
-  ref: e7682d4af0dc59291b7e7fb3d937d392982466b4
+  ref: d067f6cad78dd19a769be6c54a1f410280ce0be5
 - kind: git_module
   url: gnome:gi-docgen.git
   path: subprojects/gi-docgen