add isin implementation to the changelog

Author: ndgrigorian

CHANGELOG.md

@@ -24,6 +24,7 @@ Also, that release drops support for Python 3.9, making Python 3.10 the minimum
 * Added implementation of `dpnp.ndarray.tobytes` method [#2656](https://github.com/IntelPython/dpnp/pull/2656)
 * Added implementation of `dpnp.ndarray.__format__` method [#2662](https://github.com/IntelPython/dpnp/pull/2662)
 * Added implementation of `dpnp.ndarray.__bytes__` method [#2671](https://github.com/IntelPython/dpnp/pull/2671)
+* Added implementation of `dpnp.isin` function [#2595](https://github.com/IntelPython/dpnp/pull/2595)
 
 ### Changed