release-notes: update for 0.18.0

docs/release-notes/release-notes-0.18.0.md

@@ -167,6 +167,9 @@
   `lnd.conf`](https://github.com/lightningnetwork/lnd/pull/8310)
   for the `rpcuser` and `rpcpass` fields to better protect the secrets.
 
+* When computing a minimum fee for transaction construction, `lnd` [now takes our
+bitcoin peers' feefilter values into account](https://github.com/lightningnetwork/lnd/pull/8418).
+
 ## RPC Additions
 
 * [Deprecated](https://github.com/lightningnetwork/lnd/pull/7175)