Add release notes for 0.8.0

Author: zombiezen

CHANGELOG.md

@@ -5,9 +5,13 @@ 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]: https://github.com/zombiezen/go-sqlite/compare/v0.7.2...main
+[Unreleased]: https://github.com/zombiezen/go-sqlite/compare/v0.8.0...main
 
-## [Unreleased][]
+## [0.8.0][] - 2021-11-07
+
+Version 0.8 adds new transaction functions to `sqlitex`.
+
+[0.8.0]: https://github.com/zombiezen/go-sqlite/releases/tag/v0.8.0
 
 ### Added