Document steps to upgrade both the OS and GitLab
Problem to solve
Based on this ticket and a few others, it was highlighted that we do not explicitly document the procedure to upgrade both the OS and GitLab. There's separate docs for each, but not as one.
Other related tickets:
Further details
This addition is useful for customer who would need to upgrade their OS and GitLab and would like to verify what comes first.
Proposal
Update the section "Update GitLab package sources after upgrading the OS" in the documentation to state that one should uninstall gitlab, upgrade the OS and reinstall gitlab.