Update branch with Rebase

[alcpereira]

Is your feature request related to a problem? Please describe.
At work, we use rebase on 80% of the repos, and I want to avoid as much as possible having those merge commits due to the Update feature.

Describe the solution you'd like
The possibility to use "Update with Rebase" that is already available in the GH CLI (here).

Describe alternatives you've considered

I started working on an implementation but I would like to have some feedback regarding what would be better:

• Another keybinding: u does update with merge commit, U does update with rebase
• A config (global? repo scoped?) to override the default behaviour of u
• A prompt asking if you want to use merge or rebase (similar to lazygit when you do rebase)

[dlvhdr]

I guess another option is to contribute to gh to add interactivity similar to how the approve and merge commands work.
But I'm also ok with adding a global config option to set a default.