Fix missing service on deploy steps

.gitlab-ci.yml

@@ -63,6 +63,8 @@ docker-build-master:
 # deploy test/dev version on 'sdc-dev.astron.nl'
 docker-deploy-main-test:
   stage: deploy_to_test
+  services:
+    - docker:dind
   before_script:
     - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
     ##
@@ -103,6 +105,8 @@ docker-deploy-main-test:
 docker-deploy-main-production:
   #  image: docker:latest
   stage: deploy_to_production
+  services:
+    - docker:dind
   before_script:
     - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
     ##