fix(docker_build): init submodule submodules

due to commit e2852ebe292bc838d95048515a8dca0d93ccbc24 the submodules submodules are not being initialized, which prevents that repos files from being used.

!53

docker/build.gitlab-ci.yaml

@@ -30,6 +30,7 @@ variables:
     # See https://github.com/docker-library/docker/pull/166
     DOCKER_TLS_CERTDIR: ""
   before_script:
+    - git submodule foreach git submodule update --init
     - if [ "0$JOB_ROOT_DIR" == "0" ]; then ROOT_DIR=gitlab-ci; else ROOT_DIR=$JOB_ROOT_DIR ; fi
     - echo "[DEBUG] ROOT_DIR[$ROOT_DIR]"
     - docker info