As per the Gitlab upgrade docs: Upgrading GitLab | GitLab
13.1.11 → latest
13.12.Z → latest
14.1.Z → latest
you will need to upgrade using that path. This means upgrading to 12.10.14, make sure background migrations have finished. Then start the next upgrade on the upgrade path, and repeat. It is important to let background migrations finish: Upgrading GitLab | GitLab
The second link is direct to the background migrations part which tells you how to check and make sure it is 0 (zero) before continuing the upgrade path.
Since you are using CentOS 7, the command for upgrading would be like this:
yum install gitlab-ee-12.10.14-ee.0.el7
ce if you are using that version. You can check what you have installed with:
rpm -qa | grep -i gitlab
it will show either
gitlab-ce. Then you just amend the yum install command appropriately.
Make sure you have a backup before starting in case something goes wrong, you can restore and start again.