`System.Drawing.Common` no longer supported for non-Windows

[conficient]

Summary

Microsoft is withdrawing support for using System.Drawing.Common on non-Windows systems: https://docs.microsoft.com/en-gb/dotnet/core/compatibility/core-libraries/6.0/system-drawing-common-windows-only

There is a workaround for now but we can expect this to stop working completely at some point. They suggest one of three alternatives:

To use these APIs for cross-platform apps, migrate to one of the following libraries:

• ImageSharp
• SkiaSharp
• Microsoft.Maui.Graphics

Environment

iTextSharp.LGPLv2.Core version: 1.8.0
.NET Core SDK version: 6.x
IDE: n/a