docs(changelog) introduce 'breaking changes' header (#8600)

CHANGELOG.md

@@ -64,6 +64,15 @@
 
 ## Unreleased
 
+### Breaking Changes
+
+#### Admin API
+
+- Insert and update operations on target entities require using the `PUT` HTTP
+  method now. [#8596](https://github.com/Kong/kong/pull/8596). If you have
+  scripts that depend on it being `POST`, these scripts will need to be updated
+  when updating to Kong 3.0.
+
 ### Dependencies
 
 - Bumped pgmoon from 1.13.0 to 1.14.0
@@ -105,10 +114,6 @@
 - The cluster listener now uses the value of `admin_error_log` for its log file
   instead of `proxy_error_log` [8583](https://github.com/Kong/kong/pull/8583)
 
-#### Admin API
-
-- Insert and update operations on target entities require using the `PUT` HTTP
-  method now. [#8596](https://github.com/Kong/kong/pull/8596)
 
 ### Additions