Use `GIT_STRATEGY: none` in `stop_review_app` to make job work after successful
merges and when the branch was deleted.
Without this, the application is not stopped when the branch is deleted on merge as the runner pulls the git repository by default, but cannot find the tree in this moment.
[skip ci]
The GitLab CI examples used `$CI_ENVIRONMENT_SLUG` for defining the environment names
of the deploy jobs. But this variable is actually the OUTPUT of setting the environment name,
thus, it tries to reference itself, but does not exist in that moment.
The correct way to set this is to use `$CI_COMMIT_REF_NAME` as based on the documentation
of GitLab's dynamic environments.
