[gnome-shell] ci: Switch to mutter's docker image

[Florian Müllner <fmuellner src gnome org>]

commit 6d4b9d29b81bc043f151a9ef6f017fb29a04e371
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri May 17 20:50:00 2019 +0200

    ci: Switch to mutter's docker image
    
    Mutter's CI now also builds gnome-shell to ensure that a MR doesn't
    break the shell. Its docker image has therefore been updated to contain
    all our deps as well, so we don't need our own image anymore.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/546

 .gitlab-ci.yml        |  6 +++---
 .gitlab-ci/Dockerfile | 19 -------------------
 2 files changed, 3 insertions(+), 22 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c95799836..4b97799a3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -40,7 +40,7 @@ js_check:
         when: on_failure
 
 build:
-    image: registry.gitlab.gnome.org/gnome/gnome-shell/master:v1
+    image: registry.gitlab.gnome.org/gnome/mutter/master:v1
     stage: build
     before_script:
         - .gitlab-ci/checkout-mutter.sh
@@ -58,7 +58,7 @@ build:
             - build
 
 test:
-    image: registry.gitlab.gnome.org/gnome/gnome-shell/master:v1
+    image: registry.gitlab.gnome.org/gnome/mutter/master:v1
     stage: test
     before_script:
         - ninja -C mutter/build install
@@ -72,7 +72,7 @@ test:
         when: on_failure
 
 test-pot:
-    image: registry.gitlab.gnome.org/gnome/gnome-shell/master:v1
+    image: registry.gitlab.gnome.org/gnome/mutter/master:v1
     stage: test
     before_script:
         - ninja -C mutter/build install