replace pd append with concat

pages/Gallery.py

@@ -381,7 +381,7 @@ class GalleryApp:
             items = self.promptBook[self.promptBook['tag'] == tag].reset_index(drop=True)
             temp_items = pd.DataFrame()
             for prompt_id, selected_models in st.session_state.selected_dict.items():
-                temp_items = temp_items.append(items[items['modelVersion_id'].isin(selected_models) & (items['prompt_id'] == prompt_id)])
+                temp_items = pd.concat([temp_items, items[items['modelVersion_id'].isin(selected_models) & (items['prompt_id'] == prompt_id)]], axis=0)
             items = temp_items.reset_index(drop=True)
 
             self.checkout_mode(tag, items)