refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -8,7 +8,7 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageVersion Include="NUnit" Version="4.4.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="6.1.0" />
-    <PackageVersion Include="Polyfill" Version="9.7.7" />
+    <PackageVersion Include="Polyfill" Version="9.8.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.170" />
     <PackageVersion Include="ProjectFiles" Version="0.5.0" />
     <PackageVersion Include="System.IO.Compression" Version="4.3.0" />