Update changelog

Signed-off-by: Mateusz Szczygieł <mateusz.szczygiel@nordsec.com>

changelog.md

@@ -6,6 +6,7 @@ This means the whole API has changed. Even though semantics are the same
 the mechanism is now different and requires new implementation to use properly.
 * Split checksum events into finalize and verify
 * Add `base_dir` field in the `RequestQueued` event files
+* Fix rare issue of missing receiver's in-progress events
 
 ---
 <br>