Update release notes for 1.1.1

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/v1.1.0...main
+[Unreleased]: https://github.com/zombiezen/go-sqlite/compare/v1.1.1...main
 
-## [Unreleased][]
+## [1.1.1][] - 2024-02-02
+
+Version 1.1.1 improves performance on write-contended workloads.
+
+[1.1.1]: https://github.com/zombiezen/go-sqlite/releases/tag/v1.1.1
 
 ### Fixed