fix(ci): delete unused variables

.gitlab-ci.yml

@@ -4,12 +4,6 @@ default:
     - name: ${CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX}/docker:20.10.9-dind
       alias: docker
 
-variables:
-  DOCKER_TLS_CERTDIR: ''
-  DOCKER_HOST: tcp://docker:2375
-  DOCKER_DRIVER: overlay2
-  DEPENDENCY_PROXY: ${CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX}/
-
 stages:
   - quality
   - test