message: docs: Update GitLab auth environment variable names
  Sync with the names used in `app-config.yaml`
diff: @@ -31,8 +31,8 @@ auth:
  providers:
  gitlab:
  development:
  - clientId: ${AUTH_GITLAB_APPLICATION_ID}
  - clientSecret: ${AUTH_GITLAB_SECRET}
  + clientId: ${AUTH_GITLAB_CLIENT_ID}
  + clientSecret: ${AUTH_GITLAB_CLIENT_SECRET}
  ## uncomment if using self-hosted GitLab
  # audience: https://gitlab.company.com
  ```
  