Fix README to say that .NET 9.0 is supported (and required for build)

Author: monoman

README.md

@@ -4,9 +4,9 @@ A fork of the SvgNet & SvgGdi bridge (http://www.codeproject.com/KB/cs/svgnet.as
 
 __SvgNet is now available as a Nuget:__ [SvgNet](https://www.nuget.org/packages/SvgNet/).
 
-__Latest version 3.5.0 is .NET Standard 2.0 and 2.1 and also .NET 8.0 (base and Windows) compatible and works with .NET Core 2.x and 3.x and .NET 5.0/6.0/7.0/8.0, but now requires .NET Framework 4.6.2 or higher__
+__Latest version 3.5.0 is .NET Standard 2.0 and 2.1 and also .NET 8.0/9.0 (base and Windows) compatible and works with .NET Core 2.x and 3.x and .NET 5.0/6.0/7.0/8.0/9.0, but now requires .NET Framework 4.6.2 or higher__
 
-To build this version properly you need .NET 8.0.403+ SDK installed
+To build this version properly you need .NET 8.0.404+ & 9.0.100 SDKs installed
 
 ## License: BSD