chore(deps): update dependency to-be-continuous/docker to v2.7.1

.gitlab-ci.yml

 include:
  - project: 'to-be-continuous/docker'
-   ref: '2.7.0'
+   ref: '2.7.1'
    file: '/templates/gitlab-ci-docker.yml'
  - project: 'to-be-continuous/golang'
    ref: '2.2.0'