Bump version to v1.2.0.

CHANGELOG.md

@@ -9,6 +9,16 @@ 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
 
+## [1.2.0] - 2021-08-26
+
+### Added
+
+- Add `config.NotDefined`, `InvalidValue` and `InvalidDefaultValue` errors
+
+### Changed
+
+- Use new `config` error types as panic values instead of arbitrary strings
+
 ## [1.1.0] - 2021-07-07
 
 ### Added
@@ -94,6 +104,7 @@ the `1.0.0-rc.1` release.
 [1.0.0-rc.1]: https://github.com/dogmatiq/dogma/releases/tag/v1.0.0-rc.1
 [1.0.0]: https://github.com/dogmatiq/dogma/releases/tag/v1.0.0
 [1.1.0]: https://github.com/dogmatiq/dogma/releases/tag/v1.1.0
+[1.2.0]: https://github.com/dogmatiq/dogma/releases/tag/v1.2.0
 
 <!-- version template
 ## [0.0.1] - YYYY-MM-DD