Try to correct some bug with test project

Author: Sébastien Geiser

CodingSeb.ExpressionEvaluator.Tests/CodingSeb.ExpressionEvaluator.Tests.csproj

@@ -4,9 +4,11 @@
     <Company>Coding Seb</Company>
     <Product>CodingSeb.ExpressionEvaluator.Tests</Product>
     <Copyright>Copyright © Coding Seb 2018</Copyright>
-    <TargetFrameworks>net45;netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>net45;netcoreapp2.1</TargetFrameworks>
+    <UserSecretsId>c4ac27fa-8b9c-4784-a284-7a9a06320537</UserSecretsId>
   </PropertyGroup>
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.5.0" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
     <PackageReference Include="NUnit" Version="3.12.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.16.1">