fixed issue with updating to core 3.1

Author: EvilLord666

ReportGeneratorWeb/ReportGeneratorWeb/ReportGeneratorWeb.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <StartupObject></StartupObject>
@@ -24,11 +24,13 @@
     <PackageReference Include="Serilog.Sinks.Console" Version="4.0.1" />
     <PackageReference Include="Serilog.Sinks.File" Version="5.0.0" />
     <PackageReference Include="Serilog.Sinks.RollingFile" Version="3.3.0" />
+    <PackageReference Include="System.Text.Json" Version="6.0.0" />
   </ItemGroup>
   <ItemGroup>
     <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" />
   </ItemGroup>
   <ItemGroup>
+    <Folder Include="Models\Converters\" />
     <Folder Include="public\" />
     <Folder Include="wwwroot\files\gen\" />
     <Folder Include="wwwroot\images\" />