Updating CHANGELOG

Author: gershnik

CHANGELOG.md

@@ -16,6 +16,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - `std::atomic<intrusive_shared_ptr>::operator=` now returns `value_type` insted of `void` as is required by the
   standard.
 
+### Changed
+- `is_lock_free()` and `is_always_lock_free` for `std::atomic<intrusive_shared_ptr>` now return `false`. 
+- Size of `std::atomic<intrusive_shared_ptr>` is now greater than `sizeof(T *)` and less or equal to `2 * sizeof(T *)`
 
 ## [1.9] - 2025-05-11