pull submodules

.gitlab-ci.yml

@@ -5,6 +5,9 @@ build:
   image: docker:latest
   variables:
     DOCKER_BUILDKIT: 1
+    GIT_SUBMODULE_STRATEGY: recursive
+    GIT_SUBMODULE_DEPTH: 1
+    GIT_SUBMODULE_UPDATE_FLAGS: --jobs 4
   before_script:
     - docker info
     - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY