chore: Update CHANGELOG for #109

CHANGELOG.md

@@ -4,6 +4,16 @@ 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).
 
+## [Unreleased]
+
+### Added
+- indexed-color (256-color) rendering for `BlockImage` ([#109]).
+  - `DIRECT` and `INDEXED` render methods.
+  - *method* style-specific render parameter and format spec field.
+
+[#109]: https://github.com/AnonymouX47/term-image/pull/109
+
+
 ## [0.7.1] - 2023-02-10
 ### Fixed
 - Undefined references in some top-level functions ([497d9b7], [4e8b3e7]).