Bump System.Drawing.Common from 6.0.0 to 8.0.0

Bumps [System.Drawing.Common](https://github.com/dotnet/winforms) from 6.0.0 to 8.0.0.
- [Release notes](https://github.com/dotnet/winforms/releases)
- [Changelog](https://github.com/dotnet/winforms/blob/main/docs/release-activity.md)
- [Commits](https://github.com/dotnet/winforms/commits/v8.0.0)

---
updated-dependencies:
- dependency-name: System.Drawing.Common
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

SvgNet/SvgNet.csproj

@@ -1,10 +1,10 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
 	<PropertyGroup>
 		<TargetFrameworks>netstandard2.0;netstandard2.1;net6.0;net7.0</TargetFrameworks>
 		<TargetFrameworks Condition="'$(OS)' == 'Windows_NT'">$(TargetFrameworks);net462;net6.0-windows;net7.0-windows</TargetFrameworks>
 		<UseWindowsForms Condition="'$(TargetFramework)' == 'net6.0-windows' or '$(TargetFramework)' == 'net7.0-windows'">true</UseWindowsForms>
-		<SystemDrawingCommonVersion>6.0.0</SystemDrawingCommonVersion>
+		<SystemDrawingCommonVersion>8.0.0</SystemDrawingCommonVersion>
 		<SystemDrawingCommonVersion Condition="'$(TargetFramework)' == 'net7.0'">7.0.0</SystemDrawingCommonVersion>
 		<LangVersion>preview</LangVersion>
 		<AssemblyName>SVG</AssemblyName>