[skip ci] start a new development cycle

Author: asomers

CHANGELOG.md

@@ -3,6 +3,8 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased] - ReleaseDate
+
 ## [0.16.0] - 1 December 2019
 ### Added
 - Added `ptrace::seize()`: similar to `attach()` on Linux