Get rid of outdated changelog

CHANGELOG.md

@@ -1,19 +0,0 @@
-### 6.8.0
-- Various performance improvements
-- Fix library search query being lost
-- Upstream merge
-- Fix Tsumino and HentaiCafe links not triggering a link import
-- Fix many bugs in link interceptor
-- Completely revamp favorites sync algorithm
-- Various bug fixes
-
-### 6.6.0
-- Many performance improvements
-- Stability improvements and bug fixes
-- Upstream merge
-- Fix PervEden search
-- Add ability to use high-quality thumbnails on nhentai
-- Enable link importing for all NSFW sources
-- Fix back button in library search
-- Add HentaiCafe source
-- Add Tsumino source