Add warning about downtime during updates
Overview
When following the upgrade instructions on https://docs.gitlab.com/omnibus/update/README.html, the reader is instructed to run the upgrade commands without any warning that the upgrade could cause downtime for users.
Proposal
Add a note before the upgrade commands to warn that there will be downtime unless the Zero Downtime steps are followed.
Edited by 🤖 GitLab Bot 🤖