Make changes in unshipped.txt so the http project builds

Author: sander1095

src/Http/Http.Abstractions/src/PublicAPI.Unshipped.txt

@@ -11,3 +11,5 @@ Microsoft.AspNetCore.Http.Metadata.IParameterBindingMetadata.HasTryParse.get ->
 Microsoft.AspNetCore.Http.Metadata.IParameterBindingMetadata.IsOptional.get -> bool
 Microsoft.AspNetCore.Http.Metadata.IParameterBindingMetadata.Name.get -> string!
 Microsoft.AspNetCore.Http.Metadata.IParameterBindingMetadata.ParameterInfo.get -> System.Reflection.ParameterInfo!
+Microsoft.AspNetCore.Http.ProducesResponseTypeMetadata.Description.get -> string?
+Microsoft.AspNetCore.Http.Metadata.IProducesResponseTypeMetadata.Description.get -> string?