GHSA-XJHM-GP88-8PFX Copier safe template has arbitrary filesystem read access via symlinks when _preserve_symlinks: false

Impact Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the --UNSAFE,--trust flag. As it turns out, a safe template can currently include arbitrary files/directories outsid...