Add API Section to Changelog (#13125)

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

.changelog.yml

@@ -22,6 +22,10 @@ groups:
     name: SECURITY
     labels:
       - kind/security
+  -
+    name: API
+    labels:
+      - kind/api
   -
     name: BUGFIXES
     labels: