[gnome-shell-extensions] ci: Fix classic build

[Marge Bot <marge-bot src gnome org>]

commit 68bf3e7ff77ce804848b48a0801b55ee634747a3
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Sep 5 23:59:31 2021 +0200

    ci: Fix classic build
    
    The option name used in CI was wrong, so we did not actually build
    the auxiliary classic mode file.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/190>

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index abffa4a..18851e9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -142,7 +142,7 @@ fedora-build:
   before_script:
     - git submodule update --init
   script:
-    - meson setup build --werror -Dextension_set=all -Dclassic=true
+    - meson setup build --werror -Dextension_set=all -Dclassic_mode=true
     - meson compile -C build
     - meson test -C build
     - meson install -C build