[gssdp] ci: Really disable libsoup docs

[Jens Georg <jensgeorg src gnome org>]

commit daac73d12a42d819ce0a4f02fd412843fcf0dc50
Author: Jens Georg <mail jensge org>
Date:   Sun Apr 24 21:56:02 2022 +0200

    ci: Really disable libsoup docs

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 56bef2e..d540c4e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -78,7 +78,7 @@ check-merge-request:
 .soup3:
   before_script:
     - git clone --depth=1 https://gitlab.gnome.org/GNOME/libsoup.git && pushd libsoup
-    - meson _build --prefix=/usr -Dtls_check=false -Dgtk_doc=false
+    - meson _build --prefix=/usr -Dtls_check=false -Ddocs=disabled
     - ninja -C _build install
     - popd