Fix changelog header for 1.4.20-M1
diff --git a/ChangeLog.md b/ChangeLog.md
index 14bbd64..73f9696 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,6 +1,6 @@
 # CHANGELOG
 
-## 1.4.20
+## 1.4.20-M1
 
 ### Backend. Native