Asset: Add virtual destructor

Author: adazem009

include/scratchcpp/asset.h

@@ -18,6 +18,8 @@ class LIBSCRATCHCPP_EXPORT Asset : public Entity
         Asset(const std::string &name, const std::string &id, const std::string &format);
         Asset(const Asset &) = delete;
 
+        virtual ~Asset() { }
+
         void setId(const std::string &id);
 
         const std::string &name() const;