Describe the feature or problem you’d like to solve

I prefer when commands have man pages, even if it's mostly telling you to run with --help.

Proposed solution

I have a branch to add a basic man page and include it in builds here.
The contributing guidelines suggest opening an issue before a PR, so here we are.

I based this off how Exoscale cli packages manpages as they also use goreleaser.
It would be cool if gh also generates manpages from the same place the help flag and web documentation come from, but I don't know enough go to help with that at this point in time.