update changelog

Author: aronatkins

CHANGELOG.md

@@ -4,6 +4,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- You can now deploy Quarto documents in addition to Quarto projects. This
+  requires RStudio Connect release 2021.08.0 or later. Use `rsconnect deploy
+  quarto` to deploy, or `rsconnect write-manifest quarto` to create a manifest
+  file.
+
 ## [1.8.1] - 2022-05-31
 
 ### Changed