[evince/wip/gpoo/update-registry] ci: Use newer image

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

commit 990de548b0b61cce9130c38e1d81fdae3557a6f9
Author: Germán Poo-Caamaño <gpoo gnome org>
Date:   Mon Feb 28 20:16:51 2022 -0300

    ci: Use newer image
    
    Image based in the upcoming Ubuntu 22.04 which contains Poppler 22.02,
    latest Poppler version that contains fixes with immediate positive impact
    for Evince.
    The new CI image also contains libarchive 3.6.0, which will help remove
    code from Evince and facilitate the maintenance of the comics backend.

 .gitlab-ci.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bed27b3e8..d8eb762ea 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -7,8 +7,8 @@ stages:
 variables:
     BUNDLE: "org.gnome.Evince.flatpak"
 
-master:
-    image: registry.gitlab.gnome.org/gnome/evince/master-amd64:latest
+main:
+    image: registry.gitlab.gnome.org/gnome/evince/x86_64-ubuntu:latest
     stage: build
     when: manual