Update GraphQL.AspNetCore3 package version to 8.0.0

Author: Shane32

README.md

@@ -57,7 +57,7 @@ Below is a complete sample of a .NET 6 console app that hosts a GraphQL endpoint
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="GraphQL.AspNetCore3" Version="5.0.0" />
+    <PackageReference Include="GraphQL.AspNetCore3" Version="8.0.0" />
   </ItemGroup>
 
 </Project>