Fix changelog link

Author: bartelink

CHANGELOG.md

@@ -19,7 +19,7 @@ The `Unreleased` section name is replaced by the expected version of next releas
 ### Changed
 
 - `FsCodec.SystemTextJson` - updated to target released `System.Text.Json` v `5.0.0` binaries [#66](https://github.com/jet/FsCodec/pull/66)
-- 
+ 
 <a name="2.2.0"></a>
 ## [2.2.0] - 2021-05-05
 
@@ -180,7 +180,8 @@ Initial release based on merge of [Jet.JsonNet.Converters v0](https://github.com
 
 Final release of Jet.JsonNet.Converters archived on [v0 branch](https://github.com/jet/FsCodec/tree/v0)
 
-[Unreleased]: https://github.com/jet/FsCodec/compare/2.2.0...HEAD
+[Unreleased]: https://github.com/jet/FsCodec/compare/2.2.1...HEAD
+[2.2.1]: https://github.com/jet/FsCodec/compare/2.2.0...2.2.1
 [2.2.0]: https://github.com/jet/FsCodec/compare/2.1.1...2.2.0
 [2.1.1]: https://github.com/jet/FsCodec/compare/2.1.0...2.1.1
 [2.1.0]: https://github.com/jet/FsCodec/compare/2.0.1...2.1.0