Branch renaming support

[gmcgibbon]

I see support for branch renames in the JS client, but not here in the Ruby client. Are there any plans to add support for this? If there hasn't been any work done yet, I'd be happy to help!

Note that I'm not referring to setting a default branch. I'm referring to the new rename feature that auto-switches PR targets, inherits protection rules, etc.

[tarebyte]

For my reference, this is the endpoint in question: https://docs.github.com/en/rest/reference/repos#rename-a-branch

We're happy to 👀 pull requests @gmcgibbon ✨