nqe-0.4.0: CHANGELOG.md

# Changelog
All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).

## [Unreleased]
### Added
- Changelog and semantic versions.
- Raw TCP actors.
- Move to `package.yaml` and `hpack`.
- Type-safe asynchronous messages.
- Supervisors for `MonadUnliftIO` actions.
- Test suite.
- PubSub actor.
- Support for bounded PubSub subscribers.