[retro-gtk] ci: Use container image from gitlab.gnome.org

[Adrien Plazas <aplazas src gnome org>]

commit be7d1ca83208b70af2b4a6f480d9f0050a0deb72
Author: Exalm <exalm7659 gmail com>
Date:   Fri Apr 27 18:50:48 2018 +0500

    ci: Use container image from gitlab.gnome.org
    
    Helps avoid timeout error when pulling the image.

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 015b332..09b94f6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -8,7 +8,7 @@ stages:
   - build-flatpak
 
 flatpak:master:
-  image: registry.gitlab.com/alatiera/gnome-nightly-oci/gnome-master:latest
+  image: registry.gitlab.gnome.org/gnome/gnome-nightly-oci/nightly:master
   stage: build-flatpak
   script:
     - flatpak-builder unit-tests flatpak/org.gnome.Retro.UnitTests.json