Another attempt at fixing unit tests

Author: Krusen

BencodeNET.Tests/BencodeNET.Tests.csproj

@@ -27,6 +27,7 @@
     <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" />
+    <DotNetCliToolReference Include="dotnet-xunit" Version="2.3.0-beta1-build3642" />
   </ItemGroup>
 
   <ItemGroup>