docs: add missing version comparison link

Author: ecastro98

CHANGELOG.md

@@ -48,7 +48,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Initial release
 
-[Unreleased]: https://github.com/multitheftauto/mtasa-php-sdk/compare/v1.0.2...HEAD
+[Unreleased]: https://github.com/multitheftauto/mtasa-php-sdk/compare/v1.0.3...HEAD
+[1.0.3]: https://github.com/multitheftauto/mtasa-php-sdk/compare/v1.0.2...v1.0.3
 [1.0.2]: https://github.com/multitheftauto/mtasa-php-sdk/compare/v1.0.1...v1.0.2
 [1.0.1]: https://github.com/multitheftauto/mtasa-php-sdk/compare/v1.0.0...v1.0.1
 [1.0.0]: https://github.com/multitheftauto/mtasa-php-sdk/compare/v0.4.0...v1.0.0