Add latest branch tag for gitlab-qa images

.gitlab-ci.yml

@@ -93,6 +93,8 @@ variables:
 
   # For the default QA image, we use $CI_COMMIT_SHA as tag since it's always available and we override it for specific workflow.rules (see above)
   QA_IMAGE: "${CI_REGISTRY}/${CI_PROJECT_PATH}/gitlab-ee-qa:${CI_COMMIT_SHA}"
+  # Default latest tag for particular branch
+  QA_IMAGE_BRANCH: "${CI_REGISTRY}/${CI_PROJECT_PATH}/gitlab-ee-qa:${CI_COMMIT_REF_SLUG}"
 
   # Preparing custom clone path to reduce space used by all random forks
   # on GitLab.com's Shared Runners. Our main forks - especially the security

.gitlab/ci/build-images.gitlab-ci.yml

@@ -28,7 +28,8 @@ build-qa-image:
   script:
     - !reference [.base-image-build, script]
     - echo $QA_IMAGE
-    - /kaniko/executor --context=${CI_PROJECT_DIR} --dockerfile=${CI_PROJECT_DIR}/qa/Dockerfile --destination=${QA_IMAGE} --cache=true
+    - echo $QA_IMAGE_BRANCH
+    - /kaniko/executor --context=${CI_PROJECT_DIR} --dockerfile=${CI_PROJECT_DIR}/qa/Dockerfile --destination=${QA_IMAGE} --destination=${QA_IMAGE_BRANCH} --cache=true
 
 # This image is used by:
 # - The `CNG` pipelines (via the `review-build-cng` job): https://gitlab.com/gitlab-org/build/CNG/-/blob/cfc67136d711e1c8c409bf8e57427a644393da2f/.gitlab-ci.yml#L335