docs: remove redundant lines from changelog (afte migration from lerna to semantic-release)

Author: nodkz

CHANGELOG.md

@@ -5,10 +5,6 @@
 
 * add packages `mongodb-memory-server-global-4.2`, `mongodb-memory-server-global-4.4` ([7c97997](https://github.com/nodkz/mongodb-memory-server/commit/7c9799723e35b65f1a37204bdbc637fb0a7f622c))
 
-# Change Log
-
-All notable changes to this project will be documented in this file.
-See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
 ## [6.6.9](https://github.com/nodkz/mongodb-memory-server/compare/v6.6.8...v6.6.9) (2020-09-08)