Update changelog

Author: afilini

CHANGELOG.md

@@ -64,6 +64,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `get_internal_address` to allow you to get internal addresses just as you get external addresses.
 - added `ensure_addresses_cached` to `Wallet` to let offline wallets load and cache addresses in their database
 - Add `is_spent` field to `LocalUtxo`; when we notice that a utxo has been spent we set `is_spent` field to true instead of deleting it from the db.
+- Added `Wallet::get_signers()`, `Wallet::get_transaction()`, `Wallet::descriptor_checksum()` and `Wallet::get_address_validators()`, exposed the `AsDerived` trait.
 
 ### Sync API change