Upgrade "Microsoft.NET.Test.Sdk" to 17.12.0 to remove Newtonsoft.Json and System.Net.Http versions that have been flagged as containing known high severity vulnerabilities.

Author: leeoades

test/Stateless.Tests/Stateless.Tests.csproj

@@ -20,7 +20,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.2.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="xunit" Version="2.4.0" />
     <PackageReference Include="xunit.analyzers" Version="0.10.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />