docs: update changelog, #5841

Author: fdefelici

Diff for: CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to the versioning scheme outlined in the [README.md](RE
 
 - When a miner times out waiting for signatures, it will re-propose the same block instead of building a new block ([#5877](https://github.com/stacks-network/stacks-core/pull/5877))
 - Improve tenure downloader trace verbosity applying proper logging level depending on the tenure state ("debug" if unconfirmed, "info" otherwise) ([#5871](https://github.com/stacks-network/stacks-core/issues/5871))
+- Remove warning log about missing UTXOs when a node is configured as `miner` with `mock_mining` mode enabled ([#5841](https://github.com/stacks-network/stacks-core/issues/5841)) 
 
 ## [3.1.0.0.7]