chore: add changelog entry

Author: kantai

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to the versioning scheme outlined in the [README.md](RE
 
 ### Changed
 
+- Implement faster cost tracker for default cost functions in Clarity
 - Miner will stop waiting for signatures on a block if the Stacks tip advances (causing the block it had proposed to be invalid).
 - Logging improvements:
   - P2P logs now includes a reason for dropping a peer or neighbor