chore: add changelog fpr 3.0.0

Author: tinect

CHANGELOG_en-GB.md

@@ -1,3 +1,6 @@
+# 3.0.0
+- Add support for Shopware 6.6
+
 # 2.0.0
 - [Issue-43] (https://github.com/FriendsOfShopware/FroshProductCompare/issues/43) Shopware 6.5 compatibility
 - [Issue-33] (https://github.com/FriendsOfShopware/FroshProductCompare/issues/33) Add a new toggle in the Comparison page to show only properties have differences between products