Update .gitlab-ci.yml

.gitlab-ci.yml

@@ -1,14 +1,16 @@
 # This file is a template, and might need editing before it works on your project.
 # Official docker image.
-image: docker:latest
+image: docker:stable
 
 services:
   - docker:dind
 
 stages:
-- build
+  - build
 
 variables:
+  DOCKER_HOST: tcp://docker:2375
+  DOCKER_DRIVER: overlay2
   #IMAGE_TAG: erichardson/py-eagle-mqtt:$CI_COMMIT_TAG
   IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG