Re-enable .NET Framework support through netstandard2.0, via Serilog.Extensions.Hosting upstream

Author: nblumhardt

src/Serilog.AspNetCore/Serilog.AspNetCore.csproj

@@ -4,7 +4,7 @@
     <Description>Serilog support for ASP.NET Core logging</Description>
     <VersionPrefix>4.0.0</VersionPrefix>
     <Authors>Microsoft;Serilog Contributors</Authors>
-    <TargetFramework>netstandard2.1</TargetFramework>
+    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <AssemblyOriginatorKeyFile>../../assets/Serilog.snk</AssemblyOriginatorKeyFile>
@@ -26,15 +26,12 @@
 
   <ItemGroup>
     <PackageReference Include="Serilog" Version="2.10.0" />
-    <PackageReference Include="Serilog.Extensions.Hosting" Version="4.0.0" />
+    <PackageReference Include="Serilog.Extensions.Hosting" Version="4.1.0" />
     <PackageReference Include="Serilog.Sinks.Console" Version="3.1.1" />
     <PackageReference Include="Serilog.Sinks.File" Version="4.1.0" />
     <PackageReference Include="Serilog.Sinks.Debug" Version="2.0.0" />
     <PackageReference Include="Serilog.Settings.Configuration" Version="3.1.0" />
     <PackageReference Include="Serilog.Formatting.Compact" Version="1.1.0" />
-  </ItemGroup>
-
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.1'">
     <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="2.2.0" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="3.1.8" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.8" />

test/Serilog.AspNetCore.Tests/SerilogWebHostBuilderExtensionsTests.cs

@@ -4,14 +4,11 @@
 using System;
 using System.Linq;
 using System.Threading.Tasks;
-
 using Xunit;
-
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.AspNetCore.Builder;
-
 using Serilog.Filters;
 using Serilog.AspNetCore.Tests.Support;