Update missing changelog

CHANGELOG.rst

@@ -6,6 +6,14 @@ All notable changes to this project will be documented in this file.
 The format is based on `Keep a Changelog`_,
 and this project adheres to `Semantic Versioning`_.
 
+Unreleased
+----------
+
+Fixed
+~~~~~
+
+* Use correct HTML 5 elements for the search frontend and fix CSS accordingly.
+
 `2.0rc2`_ - 2021-06-24
 ---------------------