Chore: remove useless lines in changelog (#97)

Author: xudong963

CHANGELOG.md

@@ -5,8 +5,6 @@ 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]
-
 ## [0.1.1](https://github.com/datafusion-contrib/datafusion-materialized-views/compare/v0.1.0...v0.1.1) - 2025-01-07
 
 ### Added