Prepare next dev version

Add unreleased entry to changelog.

Signed-off-by: thc202 <[email protected]>

Author: thc202

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this GitHub action will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+
 ## [0.3.0] - 2023-06-29
 
 ### Changed
@@ -24,6 +26,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 First release to Marketplace.
 
+[Unreleased]: https://github.com/zaproxy/action-api-scan/compare/v0.3.0...HEAD
 [0.3.0]: https://github.com/zaproxy/action-api-scan/compare/v0.2.0...v0.3.0
 [0.2.0]: https://github.com/zaproxy/action-api-scan/compare/v0.1.1...v0.2.0
 [0.1.1]: https://github.com/zaproxy/action-api-scan/compare/v0.1.0...v0.1.1