Try to fix unit tests not being discovered

Author: Krusen

BencodeNET.Tests/BencodeNET.Tests.csproj

@@ -24,8 +24,13 @@
     <PackageReference Include="FluentAssertions" Version="4.19.2" />
     <PackageReference Include="NSubstitute" Version="2.0.2" />
     <PackageReference Include="xunit" Version="2.2.0" />
+    <PackageReference Include="xunit.core" Version="2.2.0" />
     <PackageReference Include="xunit.extensibility.execution" Version="2.2.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
+  </ItemGroup>
+
 </Project>