Use older Docker in Docker image version

.gitlab-ci.yml

@@ -4,7 +4,7 @@ Build Docker image:
     - tags
   image: docker:stable
   services:
-    - docker:dind
+    - docker:18.09-dind
   variables:
     DOCKER_HOST: tcp://docker:2375
     DOCKER_DRIVER: overlay2

[Christophe Benz]

Cf https://gitlab.com/gitlab-org/gitlab-runner/issues/4501#use-older-docker-in-docker-image https://about.gitlab.com/2019/07/31/docker-in-docker-with-docker-19-dot-03/