Update .changelog file to add performance label group (go-gitea#33472)

Author: lunny

.changelog.yml

@@ -22,20 +22,25 @@ groups:
     name: FEATURES
     labels:
       - type/feature
-  -
-    name: API
-    labels:
-      - modifies/api
   -
     name: ENHANCEMENTS
     labels:
       - type/enhancement
-      - type/refactoring
-      - topic/ui
+  -
+    name: PERFORMANCE
+    labels:
+      - performance/memory
+      - performance/speed
+      - performance/bigrepo
+      - performance/cpu
   -
     name: BUGFIXES
     labels:
       - type/bug
+  -
+    name: API
+    labels:
+      - modifies/api
   -
     name: TESTING
     labels: