`macos` builder failing: "The macOS-13 based runner images are now retired"

I encountered a failure when attempting to run checks using the `macos` platform. It appears that the underlying GitHub Actions runner image (`macos-13`) has been officially retired as of early December, causing the job to fail immediately during initialization. The command I used was: ```r rhub::rhub_check(platforms = "macos") ``` The build logs return the following error: ``` The macOS-13 based runner images are now retired. For more details, see https://github.com/actions/runner-images/issues/13046. The macOS-13 based runner images are being deprecated, consider switching to macOS-15 (macos-15-intel) or macOS 15 arm64 (macos-latest) instead. For more details see https://github.com/actions/runner-images/issues/13046 ``` Thanks for maintaining rhub!