Update changelog for new release

Signed-off-by: Evan Maddock <maddock.evan@vivaldi.net>

Author: EbonJaeger

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [v2.4.0] - 2021-03-08
+
 ### Changed
 
 - Use Crafatar for webhook avatar URLs instead of Minotar
@@ -76,7 +78,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Improve experience when a user sends an attachment in Discord
 
-[unreleased]: https://github.com/EbonJaeger/dolphin-rs/compare/v2.3.0...master
+[unreleased]: https://github.com/EbonJaeger/dolphin-rs/compare/v2.4.0...master
+[v2.4.0]: https://github.com/EbonJaeger/dolphin-rs/compare/v2.3.0...v2.4.0
 [v2.3.0]: https://github.com/EbonJaeger/dolphin-rs/compare/v2.2.0...v2.3.0
 [v2.2.0]: https://github.com/EbonJaeger/dolphin-rs/compare/v2.1.1...v2.2.0
 [v2.1.1]: https://github.com/EbonJaeger/dolphin-rs/compare/v2.1.0...v2.1.1