Update changelog

(cherry picked from commit 1a2d29d2)

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
+----------
+
+Added
+~~~~~
+
+* Provide API view for accessing the current PDF file of a live document (secured with OAuth2).
+
 `2.0b0`_ - 2021-11-03
 --------------------