refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -14,7 +14,7 @@
     <PackageVersion Include="Microsoft.EntityFrameworkCore.Relational" Version="9.0.9" />
     <PackageVersion Include="Microsoft.EntityFrameworkCore.Sqlite" Version="9.0.9" />
     <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.9" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageVersion Include="Microsoft.SqlServer.TransactSql.ScriptDom" Version="170.121.2" />
     <PackageVersion Include="NUnit" Version="4.4.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="5.1.0" />