[gnome-shell/gnome-3-38] ci: Update mutter image

[Marge Bot <marge-bot src gnome org>]

commit 71248f318c9833642519b5b52338186ae933a228
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Nov 20 15:56:01 2020 +0100

    ci: Update mutter image
    
    Mutter now produces an image as part of its CI pipeline. Use that
    instead of the now outdated manually built image.
    
    (cherry picked from commit e81cab540f868c76d82bbcf7867d1182620f7971)
    
    Needed for gjs from GNOME 3.38, as the 3.36 version is no longer
    enough to run the tests.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1530
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1530>

 .gitlab-ci.yml | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 95b3c2c6e3..1927c081d0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,6 +10,8 @@ variables:
     BUNDLE: "extensions-git.flatpak"
     JS_LOG: "js-report.txt"
 
+image: registry.gitlab.gnome.org/gnome/mutter/fedora/33:2020-11-20.1
+
 .only_default: &only_default
     only:
         - branches
@@ -17,7 +19,6 @@ variables:
         - merge_requests
 
 check_commit_log:
-    image: registry.gitlab.gnome.org/gnome/mutter/master:v4
     stage: review
     variables:
         GIT_DEPTH: "100"
@@ -64,7 +65,6 @@ no_template_check:
     <<: *only_default
 
 build:
-    image: registry.gitlab.gnome.org/gnome/mutter/master:v4
     stage: build
     needs: []
     before_script:
@@ -83,7 +83,6 @@ build:
             - build
 
 test:
-    image: registry.gitlab.gnome.org/gnome/mutter/master:v4
     stage: test
     needs: ["build"]
     variables: