Workaround for correct types to be referenced during serialization

The problem is passing `OneOrMany<IInterface>` is that the serializer will only look at the interface properties rather than the real types. This forces the individual types to be recognised when serializing a `OneOrMany`.

Author: Turnerj

Source/Schema.NET/ValuesJsonConverter.cs

@@ -180,7 +180,13 @@ public override void Write(Utf8JsonWriter writer, IValues value, JsonSerializerO
             }
             else
             {
-                this.WriteObject(writer, values, options);
+                writer.WriteStartArray();
+                foreach (var item in values)
+                {
+                    this.WriteObject(writer, item, options);
+                }
+
+                writer.WriteEndArray();
             }
         }