refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -14,11 +14,11 @@
     <PackageVersion Include="Microsoft.EntityFrameworkCore.Relational" Version="10.0.5" />
     <PackageVersion Include="Microsoft.EntityFrameworkCore.Sqlite" Version="10.0.5" />
     <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="10.0.5" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
     <PackageVersion Include="Microsoft.SqlServer.TransactSql.ScriptDom" Version="170.191.0" />
     <PackageVersion Include="NUnit" Version="4.5.1" />
     <PackageVersion Include="NUnit3TestAdapter" Version="6.2.0" />
-    <PackageVersion Include="Polyfill" Version="9.24.0" />
+    <PackageVersion Include="Polyfill" Version="10.0.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.172" />
     <PackageVersion Include="System.Data.SqlClient" Version="4.9.1" />
     <PackageVersion Include="Verify" Version="31.15.0" />