doc: samples: matter: lock: Add changelog entry regarding API changes.

Mention API changes in `lock` sample.

Signed-off-by: Adrian Gielniewski <adrian.gielniewski@nordicsemi.no>

Author: adigie

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -563,6 +563,7 @@ Matter samples
 * :ref:`matter_lock_sample` sample:
 
   * Removed support for nRF54H20 devices.
+  * Updated API of ``AppTask``, ``BoltLockManager`` and ``AccessManager`` to provide additional information for ``LockOperation`` event.
 
 Networking samples
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