Update release notes

Author: rachelmcr

RELEASE-NOTES.txt

@@ -8,6 +8,7 @@
 - [*] Settings: Display the WooCommerce version and available updates in Settings [https://github.com/woocommerce/woocommerce-ios/pull/7779]
 - [*] Show suggestion for logging in to a WP.com site with a mismatched WP.com account. [https://github.com/woocommerce/woocommerce-ios/pull/7773]
 - [*] Help center: Added help center web page with FAQs for "Not a WooCommerce site" and "Wrong WordPress.com account" error screens. [https://github.com/woocommerce/woocommerce-ios/pull/7767, https://github.com/woocommerce/woocommerce-ios/pull/7769]
+- [**] Reviews: Now you can reply to product reviews using the Reply button while viewing a product review. [https://github.com/woocommerce/woocommerce-ios/pull/7799]
 
 10.5
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