Bump SixLabors.ImageSharp from 3.1.7 to 3.1.11 (#24)

---
updated-dependencies:
- dependency-name: SixLabors.ImageSharp
  dependency-version: 3.1.11
  dependency-type: direct:production
...

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MapToolkit/Pmad.Cartography.csproj

@@ -26,7 +26,7 @@
 		<PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="8.0.1" />
 		<PackageReference Include="System.Text.Json" Version="8.0.5" />
 		<PackageReference Include="ZstdSharp.Port" Version="0.8.3" />
-		<PackageReference Include="SixLabors.ImageSharp" Version="3.1.7" />
+		<PackageReference Include="SixLabors.ImageSharp" Version="3.1.11" />
 		<PackageReference Include="Pmad.Geometry" Version="0.1.46" />
 		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
 	</ItemGroup>