Use .NET-specific min OS versions to build native code for .NET #10659
Description
It looks like we're going to drop support for a few older OS versions.
In particular the new min OS versions are going to be:
- iOS: 10 (.NET developers can run iOS and Android apps on emulators and devices in .NET 6 runtime#44654)
- tvOS 10 (.NET developers can run iOS and Android apps on emulators and devices in .NET 6 runtime#44654)
- macOS: 10.13 (https://github.com/dotnet/core/blob/master/release-notes/5.0/5.0-supported-os.md#macos)
We have to update our code accordingly to handle this (instead of using the min OS versions defined for legacy Xamarin)