remove CHANGELOG file since it's not needed
remove CHANGELOG file since it's not needed

It's not needed for several reasons :
- This extension is for the public, which means most of them won't even
come to the GitHub repo, and even less will read the CHANGELOG
- Notable changes are already documented using GitHub releases and the
extension's description on the Webstore

flawyte/fast-scroll,flawyte/fast-scroll,flawyte/fast-scroll,flawyte/fast-scroll