[evince/wip/gpoo/fix-flatpak-ci] ci: Remove image usage

[Germán Poo-Caamaño <gpoo src gnome org>]

commit c89accb74048b5f1422b7badc3747df1f169d455
Author: Germán Poo-Caamaño <gpoo gnome org>
Date:   Wed Aug 24 19:57:38 2022 -0400

    ci: Remove image usage
    
    The location of the image is provided in the included file. Since
    it can change, it does not make sense to keep in Evince's gitlab-ci
    definition (it can break the build silently).

 .gitlab-ci.yml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6db508e0f..e3dd2821a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -40,7 +40,7 @@ meson-internal-synctex:
         expire_in: 2 days
 
 flatpak:
-    image: registry.gitlab.gnome.org/gnome/gnome-runtime-images/gnome:master
+    extends: .flatpak
     stage: build
 
     variables:
@@ -49,7 +49,6 @@ flatpak:
         FLATPAK_MODULE: "evince"
         MESON_ARGS: "-Dnautilus=false -Dgtk_doc=false"
         APP_ID: "org.gnome.Evince"
-    extends: .flatpak
     artifacts:
         # Rewrite paths and reports to "remove" testlog.txt and junit files, 
         # which do not exists in evince build, yet.