Update CHANGELOG for 1.2.3 to document hook changes

Author: alassek

changelog.yml

@@ -1,9 +1,15 @@
 - version: 1.2.3
   date: 2025-07-29
+  added:
+    - |-
+      Add :register after-hook to detect container key registration dynamically. (via #274, @alassek)
   fixed:
     - |-
       Re-register components from manifest registrars in apps that reload the container (e.g. when
       using dry-rails and Rails development mode) (via #286, @alassek)
+  changed:
+    - |-
+      :finalize after-hook now executes before container freeze to allow mutation. (via #274, @alassek)
 - version: 1.2.2
   date: 2025-01-31
   fixed: