[feature request] Improve merge-conflict handling

[tony19]

When Ryu-Cho attempts to create a PR, but a merge conflict exists, it only logs a message to the console that tells the user to create the PR themselves. This message is hidden for the most part when dealing with GitHub Actions logs, leaving the user wondering why a PR was not created.

I think it would be more user friendly for Ryu-Cho to:

• comment on the associated issue that a merge conflict exists
• if possible, submit a PR anyway, where GitHub would automatically indicate a merge conflict
• enable configuration of this behavior