CHANGELOG: Mention serial console hang after snapshot

firecracker-microvm#5705

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Author: ilstam

CHANGELOG.md

@@ -23,6 +23,13 @@ and this project adheres to
 
 ### Fixed
 
+- [#5764](https://github.com/firecracker-microvm/firecracker/pull/5764): Fixed a
+  bug that caused the guest UART driver to get stuck and stop transmitting after
+  snapshot restore. The bug was triggered by taking a snapshot while a serial
+  transmission was taking place. On restore the driver would wait for a TX
+  interrupt that would never arrive and no output would appear in the serial
+  console.
+
 ## [1.15.0]
 
 ### Added