No need to build when not release

Signed-off-by: Martin Weise <martin.weise@tuwien.ac.at>

.gitlab-ci.yml

@@ -223,19 +223,6 @@ build-search-service:
   script:
     - "cd dbrepo-search-service && pipenv install --system --deploy"
 
-build-images:
-  image: docker.io/docker:${DOCKER_VERSION}-dind
-  stage: build
-  only:
-    - merge_requests
-  before_script:
-    - "apk add --no-cache make"
-    - echo "$CI_REGISTRY_PASSWORD" | docker login --username "$CI_REGISTRY_USER" --password-stdin $CI_REGISTRY_URL
-  script:
-    - docker build -q --network=host -t dbrepo-metadata-service:build --target build dbrepo-metadata-service
-    - docker build -q --network=host -t dbrepo-data-service:build --target build dbrepo-data-service
-    - docker compose build -q --parallel
-
 build-helm:
   image: docker.io/docker:${DOCKER_VERSION}-dind
   stage: build