Bump version to v0.3.0.

Author: jmalloc

CHANGELOG.md

@@ -9,6 +9,12 @@ 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
 
+## [0.3.0] - 2020-12-22
+
+### Added
+
+- **[BC]** Add `discoverspec.WatchResponse.Available` field
+
 ## [0.2.1] - 2020-12-22
 
 ### Fixed
@@ -34,6 +40,7 @@ The format is based on [Keep a Changelog], and this project adheres to
 [0.1.0]: https://github.com/dogmatiq/testkit/releases/tag/v0.1.0
 [0.2.0]: https://github.com/dogmatiq/testkit/releases/tag/v0.2.0
 [0.2.1]: https://github.com/dogmatiq/testkit/releases/tag/v0.2.1
+[0.3.0]: https://github.com/dogmatiq/testkit/releases/tag/v0.3.0
 
 <!-- version template
 ## [0.0.1] - YYYY-MM-DD