CHANGELOG: updates for v0.4.0

Author: ydnar

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 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]
+## [v0.4.0] — 2021-09-23
 
 ### Added
 - [#65](https://github.com/alta/protopatch/pull/56): embedded message fields. Set `(go.field).embed = true` to embed a message field in the generated Go struct. The resulting field will be a pointer to and sharing a name with the generated Go struct.
@@ -65,7 +65,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - [#21](https://github.com/alta/protopatch/issues/21) — Running `protoc` plugins other than `go` breaks on missing symbols.
 - [#15](https://github.com/alta/protopatch/pull/15) — It’s not currently possible to mix or replace existing generated struct tags.
 
-[Unreleased]: <https://github.com/alta/protopatch/compare/v0.3.4...HEAD>
+[Unreleased]: <https://github.com/alta/protopatch/compare/v0.4.0...HEAD>
+[v0.4.0]: <https://github.com/alta/protopatch/compare/v0.3.4...v0.4.0>
 [v0.3.4]: <https://github.com/alta/protopatch/compare/v0.3.3...v0.3.4>
 [v0.3.3]: <https://github.com/alta/protopatch/compare/v0.3.2...v0.3.3>
 [v0.3.2]: <https://github.com/alta/protopatch/compare/v0.3.1...v0.3.2>