Add changelog entry.

CHANGES.md

@@ -10,6 +10,7 @@ Fixed Issues:
 * [#2996](/~https://github.com/ckeditor/ckeditor4/issues/2996): Fixed: Table header "scope" attribute is incorrect for the "Headers: both" option in the [Table](https://ckeditor.com/cke4/addon/table) dialog.
 * [#4802](/~https://github.com/ckeditor/ckeditor4/issues/4802): Fixed: [Tableselection](https://ckeditor.com/cke4/addon/tableselection) caret moves to the previous cell after tabbing into the next cell and then removing its content.
 * [#5365](/~https://github.com/ckeditor/ckeditor4/issues/5365): Fixed: The value of the [`config.baseFloatZIndex`](https://ckeditor.com/docs/ckeditor4/latest/api/CKEDITOR_config.html#cfg-baseFloatZIndex) config variable is incorrectly applied to parent dialog when the child dialog is closed resulting in the dialog overlay covering up the dialog. Thanks to [JenoDK](/~https://github.com/JenoDK)!
+* [#5305](/~https://github.com/ckeditor/ckeditor4/issues/5305): Fixed: Anchor name can invalidly include spaces.
 
 ## CKEditor 4.20