Add changelog item

Author: gumb0

CHANGELOG.md

@@ -16,5 +16,6 @@
 - Fixed: [#5523](https://github.com/ethereum/aleth/pull/5523) [#5533](https://github.com/ethereum/aleth/pull/5533) Fix syncing terminating prematurely because of race condition.
 - Fixed: [#5539](https://github.com/ethereum/aleth/pull/5539) Fix logic for determining if dao hard fork block header should be requested.
 - Fixed: [#5547](https://github.com/ethereum/aleth/pull/5547) Fix unnecessary slow-down of eth_flush RPC method.
+- Fixed: [#5548](https://github.com/ethereum/aleth/pull/5548) Fix rlp tool for long hexadecimal string inputs
 
-[1.6.0]: https://github.com/ethereum/aleth/compare/v1.6.0-alpha.1...release/1.6
+[1.6.0]: https://github.com/ethereum/aleth/compare/v1.6.0-alpha.1...release/1.6