Add pending changelog noting possible backwards compat panic

wpaulino · wpaulino · commit a1b53947c0cf · 2023-03-28T13:24:07.000-07:00
diff --git a/pending_changelog/2059.txt b/pending_changelog/2059.txt
@@ -0,0 +1,4 @@
+## Backwards Compatibility
+
+- Providing `ChannelMonitorUpdate`s generated by LDK 0.0.115 to a
+`ChannelMonitor` on 0.0.114 or before may panic.
