Update to gitlab-ce 13.0.5.
Changelog:
https://about.gitlab.com/releases/2020/05/06/gitlab-com-13-0-breaking-changes/
https://about.gitlab.com/releases/2020/05/22/gitlab-13-0-released/
https://about.gitlab.com/releases/2020/05/27/security-release-13-0-1-released/
https://about.gitlab.com/releases/2020/05/29/gitlab-13-0-3-released/
https://about.gitlab.com/releases/2020/06/03/critical-security-release-13-0-4-released/

Make sure you read the upgrade manual very carefully, there is a manual change in file:
/usr/local/share/gitaly/config.toml
required that the diff does not show.