More documentation required for when upgrading omnibus package

A GitLab user has expressed the following about the documentation suite:

Further none of those pages explains how to pass in a specific version of the omnibus package to satisfy the upgrade process in the even that the latest version fails because the upgrade version differential is not supported.

This was posted here: https://news.ycombinator.com/item?id=18027577.

We need to make the documentation explain all information required during upgrade process to make the upgrade process as smooth as possible.

New doc or update?

• New documentation
• Update existing documentation

Checklists

Product Manager

• Add the correct labels
• Add the correct milestone
• Indicate the correct document/directory for this feature
• Fill the doc blurb below

Documentation blurb

• Doc title

• Feature overview/description

• Feature use cases

Developer

• Copy the doc blurb above and paste it into the doc
• Write the tutorial - explain how to use the feature
• Submit the MR using the appropriate MR description template