[gnome-runtime-images] ci: only push the old tags for 40 and master tags

[Jordan Petridis <jpetridis src gnome org>]

commit 716afaade9ffa269f8ee7ab3d39d8547d5f24386
Author: Jordan Petridis <jordan centricular com>
Date:   Mon Oct 18 04:32:35 2021 +0300

    ci: only push the old tags for 40 and master tags
    
    We should transition to the new unified image tag with 41+
    and we can make the deprecated tags obselete in the future

 .gitlab-ci.yml | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bc6c005..2308d29 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -95,8 +95,11 @@ flat-manager-client:
               echo "Pushing $TAG"
               buildah tag $TAG $LLVM_TAG $RUST_TAG
               buildah push $TAG
-              buildah push $LLVM_TAG
-              buildah push $RUST_TAG
+
+              if [ $BRANCH == "master" ] || [ $BRANCH == "40" ]; then
+                buildah push $LLVM_TAG
+                buildah push $RUST_TAG
+              fi
           fi
 
 .vars_nightly: