try to install apt-get

.gitlab-ci.yml

@@ -52,8 +52,8 @@ build-ubuntu:
     - docker
   stage: build
   script:
-    - apt-get update
     - apk update ; apk add git apt-get
+    - apt-get update
     # - git checkout master -- requirements.txt
     - docker build --pull -t "$CI_REGISTRY_IMAGE/install-ubuntu" for_build/ubuntu
     - docker push "$CI_REGISTRY_IMAGE/install-ubuntu"