Add missing pending changelog for downgrade on unsafe funding

diff --git a/pending_changelog/3259-no-downgrade.txt b/pending_changelog/3259-no-downgrade.txt
new file mode 100644 (file)
index 0000000..ed4193d
--- /dev/null
+++ b/pending_changelog/3259-no-downgrade.txt
@@ -0,0 +1,4 @@
+# Backwards Compatibility
+ * Downgrading after using `ChannelManager`'s
+   `unsafe_manual_funding_transaction_generated` may cause deserialization of
+   `ChannelManager` to fail with an `Err` (#3259).