build only ubuntu image, without loading requirements.txt nor install git

.gitlab-ci.yml

@@ -52,9 +52,7 @@ build-ubuntu:
     - docker
   stage: build
   script:
-    - apk update ; apk add git
-    - apk search -v
-    # - apt-get update
+    - apk update  # ; apk add git
     # - git checkout master -- requirements.txt
     - docker build --pull -t "$CI_REGISTRY_IMAGE/install-ubuntu" for_build/ubuntu
     - docker push "$CI_REGISTRY_IMAGE/install-ubuntu"