fixed broken Nhibernate tests

Author: osoykan

test/Stove.NHibernate.Tests/Stove.NHibernate.Tests.csproj

@@ -14,6 +14,8 @@
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="NSubstitute" Version="3.1.0" />
     <PackageReference Include="System.Data.SQLite.Core" Version="1.0.108" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.7.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
   </ItemGroup>                   
 
 </Project>