Set the minimum supported OS to macOS 12, dropping support for macOS 11.
Justification is twofold:
Apple only supports "current - 2" versions with security updates. Santa aims to meet this goal as well. This means macOS 11 hasn't been supported in some time already.
The macOS 11 test runners are being removed on GitHub, so we don't have a automated test pipeline anymore.
Set the minimum supported OS to macOS 12, dropping support for macOS 11.
Justification is twofold: