Bump min OS versions in .NET 11?

[rolfbjarne]

Currently waiting for news from dotnet/runtime to see if they're bumping min OS versions.

References:

• .NET 9 issue: Bump min OS versions in .NET 9 #19392.
• .NET 10 issue: Bump min OS versions in .NET 10? #21367.
• dotnet/runtime: Consider bumping minimum iOS / tvOS version to 13 runtime#120457