Bump version to v0.3.1.

CHANGELOG.md

@@ -10,6 +10,17 @@ The format is based on [Keep a Changelog], and this project adheres to
 [keep a changelog]: https://keepachangelog.com/en/1.0.0/
 [semantic versioning]: https://semver.org/spec/v2.0.0.html
 
+## [0.3.1] - 2023-08-15
+
+### Changed
+
+- Dropped support for Go v1.19, which reached end-of-life on 2023-08-08
+
+### Fixed
+
+- Removed use of `golang.org/x/exp` package. This package is not versioned and
+  as such breaking changes can cause conflicts with other dependencies
+
 ## [0.3.0] - 2023-04-01
 
 ### Added
@@ -80,6 +91,7 @@ The format is based on [Keep a Changelog], and this project adheres to
 [0.1.3]: https://github.com/dogmatiq/dissolve/releases/tag/v0.1.3
 [0.2.0]: https://github.com/dogmatiq/dissolve/releases/tag/v0.2.0
 [0.3.0]: https://github.com/dogmatiq/dissolve/releases/tag/v0.3.0
+[0.3.1]: https://github.com/dogmatiq/dissolve/releases/tag/v0.3.1
 
 <!-- version template
 ## [0.0.1] - YYYY-MM-DD

go.mod

@@ -1,6 +1,6 @@
 module github.com/dogmatiq/dissolve
 
-go 1.19
+go 1.20
 
 require (
 	github.com/miekg/dns v1.1.55