Describe the feature or problem you’d like to solve

I want to avoid memorizing assignees' login names, therefore I'd like to be able to select assignees interactively when opening a pull request.

Currently, I can get close to what I'm looking for by invoking gh pr create... && gh pr edit. However pr edit asks which fields of the PR you'd like to edit, which is redundant in this case as I only want to add assignees.

Proposed solution

I suggest to either:

1. Add a flag to pr edit that allows one to select which fields they'd like to edit interactively. e.g. gh pr edit --interactively assignees
2. Add a flag to pr create that allows you to add assignees interactively after opening a PR.

I like the first solution better because it doesn't depend on a PR being created.