meta: use std::identity instead of entt::identity

src/entt/meta/context.hpp

@@ -1,6 +1,7 @@
 #ifndef ENTT_META_CTX_HPP
 #define ENTT_META_CTX_HPP
 
+#include <functional>
 #include <memory>
 #include "../container/dense_map.hpp"
 #include "../core/fwd.hpp"
@@ -15,7 +16,7 @@ namespace internal {
 struct meta_type_node;
 
 struct meta_context {
-    dense_map<id_type, std::unique_ptr<meta_type_node>, identity> value;
+    dense_map<id_type, std::unique_ptr<meta_type_node>, std::identity> value;
 
     [[nodiscard]] inline static meta_context &from(meta_ctx &);
     [[nodiscard]] inline static const meta_context &from(const meta_ctx &);