[mutter] ci: Always retry the image build step

[Robert Mader <rmader src gnome org>]

commit a4e71361b6ac8ae5f607d59257ec85543f57d802
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Aug 10 13:09:19 2022 +0200

    ci: Always retry the image build step
    
    The image build step is prone to race conditions, e.g. token changes. It
    also tends to hit sporadic connection errors to FDO's gitlab. To
    minimize the risk of these types of issues block pipelines, always retry
    the image building step if it failed.
    
    This has the unwanted consequence that changes to the image building
    that results in the script actually failing, but right now there doesn't
    appear to be a way to distinguish between actual build errors, and the
    mentioned race conditions, as both cause the script to fail.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2564>

 .gitlab-ci.yml | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ac05fec5fa..77eb14ee42 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -115,6 +115,10 @@ variables:
         cd .. &&
         rm -rf virtme
       fi
+  retry:
+    max: 2
+    when:
+      - 'always'
 
 default:
   # Cancel jobs if newer commits are pushed to the branch