Describe the feature or problem you’d like to solve

GitHub recently announced PR auto-merge to automatically merge PRs when all checks are passing and the PR is approved with no conflicts.

Proposed solution

We can support this in GitHub CLI. Here's the proposed design:

gh pr merge --auto to enable automerge on a PR.
gh pr merge --auto-disable to disable automerge on a PR.

Additional context

This feature won't be GA until sometime in the next couple months, so we should wait until it's broadly available to ship this in GitHub CLI.