Test and require Git 2.21
Prior to this change, Git 2.18 was the minimal version GitLab required. This commit will require 2.21. This allows GitLab to leverage newer Git features.
Part of: https://gitlab.com/gitlab-org/gitlab-ce/issues/54255
Prior to this change, Git 2.18 was the minimal version GitLab required. This commit will require 2.21. This allows GitLab to leverage newer Git features.
Part of: https://gitlab.com/gitlab-org/gitlab-ce/issues/54255