Fixed invalid json in sample

Author: niemyjski

sample/SampleWeb/Program.cs

@@ -1,11 +1,6 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Logging;
 using Serilog;
 
 namespace SampleWeb

sample/SampleWeb/appsettings.json

@@ -4,7 +4,7 @@
             "Default": "Information",
             "Override": {
                 "Microsoft": "Warning",
-                "System": "Warning"
+                "System": "Warning",
                 "SampleWeb.Authentication.TestAuthenticationHandler": "Warning"
             }
         }