Update CHANGELOG.md

Author: Shnatsel

cargo-cyclonedx/CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## 0.5.0 - 2024-02-27
+## 0.5.0 - UNRELEASED
 
 ### Added
 
@@ -92,4 +92,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#619]: https://github.com/CycloneDX/cyclonedx-rust-cargo/pull/619
 [#620]: https://github.com/CycloneDX/cyclonedx-rust-cargo/pull/620
 [#630]: https://github.com/CycloneDX/cyclonedx-rust-cargo/pull/630
-[#634]: https://github.com/CycloneDX/cyclonedx-rust-cargo/pull/634
+[#634]: https://github.com/CycloneDX/cyclonedx-rust-cargo/pull/634