refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -10,7 +10,7 @@
     <PackageVersion Include="GeoJSON.Net" Version="1.4.1" />
     <PackageVersion Include="HtmlAgilityPack" Version="1.12.3" />
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0-beta.2" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageVersion Include="Microsoft.Sbom.Targets" Version="4.1.2" />
     <PackageVersion Include="NetTopologySuite" Version="2.6.0" />
     <PackageVersion Include="NetTopologySuite.IO.GeoJSON" Version="4.0.0" />