docs: add release-notes for LND 20.1

docs/release-notes/release-notes-0.20.1.md

@@ -37,6 +37,12 @@
   prevent a node from starting up if two goroutines attempt to update the 
   node's announcement at the same time.
 
+* [Fix timestamp comparison in source node
+  updates](https://github.com/lightningnetwork/lnd/pull/10449) that could still
+  cause "sql: no rows in result set" startup errors. The previous fix (#10371)
+  addressed concurrent updates with equal timestamps, but the seconds-only
+  comparison could still fail when restarting with different minute/hour values.
+  
 * [Fix a startup issue in LND when encountering a 
   deserialization issue](https://github.com/lightningnetwork/lnd/pull/10383) 
   in the mission control store. Now we skip over potential errors and also