posts: 3.16: add note about ICU data split

posts/Alpine-3.16.0-released.md

@@ -45,7 +45,9 @@ the v3.16 stable series.
   The [preferred][login-utils] implementation is from `util-linux`.
 * [NetworkManager plugins][nm-plugins] have moved to subpackages and are no longer installed by default.
   Users may need install plugins to not lose network connectivity.
-  
+* The ICU data [has been split][13] into [icu-data-en][14] (default) and [icu-data-full][15] packages.
+  Users may need to install `icu-data-full` for non-English locales or legacy charset converters support.
+
 <a name="deprecation_notes">Deprecation notes</a>
 -----------------
 
@@ -80,6 +82,9 @@ hosting.
 [10]: https://gitlab.alpinelinux.org/alpine/aports/issues?scope=all&utf8=%E2%9C%93&state=closed&milestone_title=3.16.0
 [11]: https://pkgs.alpinelinux.org/packages?name=doas
 [12]: https://pkgs.alpinelinux.org/packages?name=doas-sudo-shim
+[13]: https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.16.0#ICU_data_split
+[14]: https://pkgs.alpinelinux.org/packages?name=icu-data-en
+[15]: https://pkgs.alpinelinux.org/packages?name=icu-data-full
 [login-utils]: https://gitlab.alpinelinux.org/alpine/aports/-/issues/13420
 [nm-plugins]: https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.16.0#NetworkManager_plugins