Add development stub after 0.20.0 release

Author: ndgrigorian

CHANGELOG.md

@@ -4,6 +4,16 @@ 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).
 
+## [dev] - XXX. XX, XXXX
+
+### Added
+
+### Change
+
+### Fixed
+
+### Maintenance
+
 ## [0.20.0] - XXX. XX, XXXX
 
 ### Added