gitlab-ci: Update to latest ci-templates HEAD

Among other things, this increases robustness when copying a docker
image from the main Mesa project to a forked project, avoiding spurious
image rebuilds from scratch.

Also drop the comment about .gitlab-ci/lava-gitlab-ci.yml, it doesn't
include the templates anymore.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3643>

.gitlab-ci.yml

@@ -3,8 +3,7 @@ variables:
 
 include:
   - project: 'wayland/ci-templates'
-    # Must be the same as in .gitlab-ci/lava-gitlab-ci.yml
-    ref: 0a9bdd33a98f05af6761ab118b5074952242aab0
+    ref: b7030c2cd0d6ccc5f6d4f8299bafa4daa9240d71
     file: '/templates/debian.yml'
   - local: '.gitlab-ci/lava-gitlab-ci.yml'