Upgrade OS at docker

After las update Gitlab CE (now i have version 13.9.1), it wrote me, that ubuntu 16.04 will be depredicate.

If i dont find a way how to upgrade OS at docker, what to do?

How to update OS at docker? If it is not possible, how update docker image without data lost?

I have docker image at windows 10. I can not find where gitlab get OS version… sorry, I’m not docker / gitlab expert

What to do::
docker exec -it gitlab /bin/bash
then
apt install update-manager-core
then
do-release-upgrade