use docker buildkit

images.gitlab-ci.yml

@@ -11,6 +11,7 @@ variables:
   DOCKER_PREPARE_CMD: docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
   DOCKER_LOGIN_CMD: docker login ${IMAGE_SERVER} --username ${DOCKER_USERNAME} --password ${DOCKER_PASSWORD}
   DOCKER_LOGOUT_CMD: docker logout ${IMAGE_SERVER}
+  DOCKER_BUILDKIT: 1
 
 # Required vars:
 ## IMAGE_PATH