ci: use Docker DinD version from variable

.gitlab-ci.yml

@@ -31,7 +31,7 @@ run-pre-commit:
 build:
   stage: build
   services:
-  - docker:dind
+  - docker:${DOCKER_DIND_VERSION}
   script:
   - build
   - curl -Os https://uploader.codecov.io/latest/linux/codecov