Add release note for shipping labels package caching

Author: irfano

RELEASE-NOTES.txt

@@ -12,6 +12,7 @@
 - [WEAR] Updated UserAgent of API requests to use `http.agent` System Property to fix performance issues related to WebView usage on app launch [https://github.com/woocommerce/woocommerce-android/pull/14431]
 - [***] POS: A new settings to customize the POS [https://github.com/woocommerce/woocommerce-android/pull/14527]
 - [*] [Login] Improved the detection of WooCommerce API version during login flow [https://github.com/woocommerce/woocommerce-android/pull/14524]
+- [*] Shipping Labels: Adds caching to the "Select a Package" screen [https://github.com/woocommerce/woocommerce-android/pull/14541]
 
 23.1
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