docs: update release notes

Author: bhandras

release_notes.md

@@ -19,5 +19,7 @@ This file tracks release notes for the loop client.
 #### Breaking Changes
 
 #### Bug Fixes
+* Bump minimum LND version to v0.15.1-beta to avoid failed swaps due to the chain
+  backend not properly supporting taproot (fixed in: https://github.com/lightningnetwork/lnd/pull/6798).
 
 #### Maintenance