Update caching to v8.0.0 on .NET 8.0 build (#511)

Fixes #488

Author: twsouthwick

src/Microsoft.AspNetCore.SystemWebAdapters/Microsoft.AspNetCore.SystemWebAdapters.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFrameworks>net6.0;net8.0;netstandard2.0;net45;net472</TargetFrameworks>
@@ -33,10 +33,22 @@
     <Compile Include="HtmlString.cs" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net6.0' OR '$(TargetFramework)' == 'net8.0' ">
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net6.0' ">
+
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
 
     <PackageReference Include="System.Runtime.Caching" Version="6.0.0" />
+
+    <Using Include="Microsoft.AspNetCore.Http.HttpContext" Alias="HttpContextCore" />
+    <Using Include="Microsoft.AspNetCore.Http.HttpResponse" Alias="HttpResponseCore" />
+    <Using Include="Microsoft.AspNetCore.Http.HttpRequest" Alias="HttpRequestCore" />
+  </ItemGroup>
+
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net8.0' ">
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+
+    <PackageReference Include="System.Runtime.Caching" Version="8.0.0" />
+
     <Using Include="Microsoft.AspNetCore.Http.HttpContext" Alias="HttpContextCore" />
     <Using Include="Microsoft.AspNetCore.Http.HttpResponse" Alias="HttpResponseCore" />
     <Using Include="Microsoft.AspNetCore.Http.HttpRequest" Alias="HttpRequestCore" />