title: Found errors in your .gitlab-ci.yml: unknown keys in `extends`
body: <p>My code for the pipeline is:</p>
  <pre><code>include:
   - template: Terraform/Base.gitlab-ci.yml  # https://gitlab.com/gitlab-org/gitlab/blob/master/lib/gitlab/ci/templates/Terraform/Base.latest.gitlab-ci.yml
  stages:
   - init
   - validate
   - build
   - deploy
  init:
   extends: .init
  validate:
   extends: .validate
  build:
   extends: .build
  deploy:
   extends: .deploy
   dependencies:
     - build
  </code></pre>
  <p>The error message I'm getting is:</p>
  <pre><code>Found errors in your .gitlab-ci.yml:  
  init: unknown keys in extends (.init)  
  You can also test your .gitlab-ci.yml in CI Lint
  </code></pre>