Fix an error with fetching nil for the gitlab-monitor version
Fixes: https://gitlab.com/charts/gitlab/issues/1398
Fixes a bug set by: https://gitlab.com/charts/gitlab/merge_requests/834
You can verify the script doesn't throw an exception by running it in dry-run mode:
./scripts/manage_version.rb --dry-run --app-version=12.0.2 -a
Edited by DJ Mountney