[xdg-desktop-portal-gnome] CI: Fix CI trying to rebuild gnome-desktop

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 593b8a1e361a3b9881303feb73113d61a5bf22a4
Author: knuxify <knuxify gmail com>
Date:   Tue Dec 21 07:55:06 2021 +0100

    CI: Fix CI trying to rebuild gnome-desktop

 .gitlab-ci.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 91e2bdc..023a02e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -20,7 +20,8 @@ build-fedora:
     - git clone https://gitlab.gnome.org/GNOME/gnome-desktop.git &&
       cd gnome-desktop &&
       meson . _build --prefix /usr -Ddesktop_docs=false &&
-      ninja -C _build install
+      ninja -C _build install &&
+      cd ..
 
 build-ubuntu:
   image: ubuntu:rolling
@@ -36,4 +37,5 @@ build-ubuntu:
     - git clone https://gitlab.gnome.org/GNOME/gnome-desktop.git &&
       cd gnome-desktop &&
       meson . _build --prefix /usr -Ddesktop_docs=false &&
-      ninja -C _build install
+      ninja -C _build install &&
+      cd ..