refs or cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -5,10 +5,10 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageVersion Include="NUnit" Version="4.5.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="6.1.0" />
-    <PackageVersion Include="Polyfill" Version="9.11.0" />
+    <PackageVersion Include="Polyfill" Version="9.12.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.172" />
     <PackageVersion Include="System.Drawing.Common" Version="10.0.3" />
     <PackageVersion Include="Verify" Version="31.13.2" />