Revert "Release 0.12.0 (#326)"

This reverts commit d4e09a9.

Author: yngvar-antonsson

CHANGELOG.md

@@ -5,8 +5,6 @@ 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]
-
-## [0.11.0] - 2021-11-18
 ### Changed
 - Update `http` dependency to 1.1.1