refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -11,7 +11,7 @@
     <PackageVersion Include="GraphQL.Server.Transports.AspNetCore" Version="8.3.3" />
     <PackageVersion Include="GraphQL.Server.Ui.GraphiQL" Version="8.3.3" />
     <PackageVersion Include="GraphQL.SystemTextJson" Version="8.8.3" />
-    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0" />
+    <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.1" />
     <PackageVersion Include="Microsoft.AspNetCore.Mvc.Testing" Version="10.0.3" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.3" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
@@ -23,7 +23,7 @@
     <PackageVersion Include="xunit.v3" Version="3.2.2" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
     <PackageVersion Include="Argon" Version="0.33.5" />
-    <PackageVersion Include="DiffEngine" Version="18.4.2" />
+    <PackageVersion Include="DiffEngine" Version="19.0.0" />
     <PackageVersion Include="EmptyFiles" Version="8.17.2" />
     <PackageVersion Include="SimpleInfoName" Version="3.2.0" />
     <PackageVersion Include="Verify" Version="31.13.2" />